mikeyk101

That is a most excellent suggestion about switching to a diesel but I only make a couple trips a year towing the toyhauler so I can't quite justify the switch right now. The truck is long paid off and regular use doesn't require the extra umph a diesel would give me. That coupled with the recent cost of diesel fuel, I will be staying with the gasser for now.

The cleaning at end of summer was much more thorough and bugs are not a big problem in the part of Wisconsin where I stay. A good rinsing is usually enough but I have a lot of time after this trip to do it again and check.

Not a regular drive luckily. Usually a lot flatter but even in places with grades like I mentioned, they are not the ungodly long distance that this one was so more up and downs. I agree with you and @diyer2that the stupid choice of octane was a big factor. After tomorrow, I will be headed back east towards home at a more leisurely pace and not sure what route I will be taking but won't go any lower than my usual 87 octane especially when towing.

Bad gas could have been a possibility too. The thing about this road is that when leaving Buffalo, you are at city speeds and it goes almost right into the climb so there isnt much chance to build up speed. Yes, I probably should have let my foot off the gas a bit more and just let it slow down but was traveling with and behind another couple that was just towing a much lighter 6x12 enclosed V nose cargo trailer with their pickup. In the past, I had always been able to at least maintain the speeds without too much of a struggle but I guess never tackled a mountain route of this magnitude. The other couple were going just under speed limit so I figured I would be ok too. This part of 16 climbs for quite a few miles without any downhill runs. I couldn't find exactly how long the first part does this but it is many miles. After that first loooong climb, it then starts a more reasonable up and down until you exit the mountains. On the rest of the Big Horn mountain road, it did just fine. Temps would rise and fall but never got back up to what it was on that first part. Once out of that mountain range, temps were normal. But it did seem to lack the regular power I'm used to on the flatter terrain. I'm just glad my route took me down 16 instead of WY-14 or even 14A as I have been told that those are even a more difficult highway to tackle while towing.

I did forget to mention I always used the tow-haul when towing it. The RPM's ended up going into the upper 4k and lower 5k. I honestly don't know what gear it was in while in "D" but we where traveling in the 55-60mph range. I found out that the highest elevation on this highway is at 9677 feet. My truck is a 2016 and has almost 70,000 miles. And surprisingly, I did check for bugs in front of condenser prior to this trip and gave it a good rinsing. I did a more thorough cleaning of it at the end of last summer.

I think I just learned a valuable lesson. I have towed through the mountains pulling my toyhauler before through the elevations in places like Tennessee, Arkansas, etc... and have always put "regular" gas in it. It is a 5.3l with a 6l80 trans with new updated thermostat and 3.42 rear end. The toyhauler is a 25' and is probably in the range of 6200lbs loaded. The regular I've put in has always been 87 octane. Fast forward to yesterday. My journey put me going down 16 in Wyoming from Buffalo as I was headed to Cody but I need to get fuel before I started into the Big Horn Mountains. So without thinking, I put in "regular" gas which I always do but happen to notice it's 85.5 octane. I was low and think I put in about 22 gallons. And with the obvious current gas pricing, I have always gone with the cheapest that worked. So now I head out of Buffalo and start the uphill climb. It's a pretty serious grade that seems to be neverending. I want to say it was a 6-7% grade that went on for miles. As I'm climbing, it seems to lack power. I have to mash the accelerator to the floor and even drop the shifter from "D" to "M" which is a trick I've used many times before to help maintain speeds up grades. Usually in situations like this, I dont even need to have to have the accelerator fully floored and can sometimes even drop back a bit on the accelerator and still keep up the speed. This time was different. I was able to maintain a speed of maybe 55-60mph but it was struggling. I had my Bluetooth OBD11 reader connected and was monitoring the oil, cooling, and trans temps. I saw all of them steadily climbing. IIRC, several miles into this climb, I get a message that the air conditioning was being turned off because of engine heat. Eventually the coolant temp hit 260⁰ and a warning to let the engine idle to cool it off. I believe the trans temp got right around the 240⁰ mark as well. Unfortunately, I had wanted to pull over before it got that high but there were no pulloffs to do this. Luckily when that last warning came on, I did just reach one and pulled over and let it idle. Coolant temp dropped as well as trans temp too. After coolant got down to about 220⁰, I pulled back out. The grade continued upward for a bit more but I got through it. I did hit a couple more uphill grades but coolant never got back up to 260⁰ again. I did find myself with accelerator all the way to the floor and could maintain speed but not accelerate any more. Once out of the Big Horns, the coolant and trans temps never got anywhere near the levels they did in the mountains but I definitely noticed a lack of power. I'm pretty convinced that most of the problems were because of using the 85.5 octane gas. I think it would have gone much better if I had gone with 87 octane. I will find out if I'm correct in about 2 days as I make the journey back east. Not quite sure what route I am taking though but strong possibility it will end up taking me back through the Big Horns.

No, I didnt check the gaps or resistance but on the us side, I kept them all and actually kept them in order so I know which plug came from which cylinder. I will be gone for about 2 weeks on my trip buy will take a look once I get back home.

Interesting that you bring up the Gumout. I have had really good success with Chevron Techron and previous vehicles and decided today to dump a bottle into the tank. I was at just over a half tank and had a trip of around 150 miles. But with the dealer installing the new injector in Cyl 1 and new plugs for all the cylinders, it was already running fine. I just figured it might be a good idea on the 7 other injectors. I also tonight went an calibrated the speedometer back to the custom Rough Country program as I like having the speedometer to be closer to actual speed. I leave for Custer SD tomorrow morning towing the toyhauler. Everything is ready to go and hopefully it is a very enjoyable uneventful trip.

Well at over 2 million miles on a 7 year old truck, I'm guessing there's quite a few things besides the coils that are due for replacement...

All I can say is that cylinder #8 can SUCK IT!!! Wow, what a pain. Drivers side wasn't bad except the drive shaft in the way for #5 but still not bad. Passenger cylinders were a bit more challenging as less room available. Then comes cylinder #8... Can't even see the spark plug once the boot was off. I had to do it completely by feel and had to twist my body in ways that I don't think God meant me to. When looking at it I was very tempted to just say screw it and run with 7 new plugs and call it a day. But I knew it would keep eating at me so I dived in. Somehow I got it. I swear that it took almost as long to accomplish as all the other 7 combined. Well almost. Luckily I have a nice assortment of extensions including several wobbly ones too. I really have to remember that the next time I do this, I have to pick another day where it's not 96⁰. Overall, each plug looked about the same. Even #1 and #2. They definitely looked used but didn't look too bad. Here are screenshots of cylinder 1 plugs first which was the one that had the injector replaced and then #2 which kept showing me several misfires when cold and then smoothed out.

Spark plugs now in hand. Just gotta wait for the motor to cool down a little bit more. I didn't get around to ordering the new wire set yet, I'm a terrible procrasinator... but at least now I will be pulling the old plugs to check them and get the new ones in. Oreilly is supposed to give me $24 in store gift cards once I submit the rebate and then I will also submit the rebate request to AC Delco for another $24 in rebates. I also had a $10 O'Reilly Rewards so after tax, each plug comes out to $3.22. Not bad.

The OEM ACDelco plugs called for in my 5.3L Silverado that I am picking up tomorrow are 41-114 Iridium plugs.

The way it was explained to me many years ago... Especially on 4wd vehicles where the lug nuts are also part of securing the brake rotors, torquing is a must. If this isn't done, and even torque isnt applied to every lug nut, there is a strong possibility that the rotors will warp and you end up with the dreaded pulsing brake pedal. I was warned about this when I was much younger and had brought in another truck for service because of a pulsing brake problem. The pads still had a lot of life yet but they obviously had to be changed out as well. Ever since then, any time any of the wheels come off for service, I always double check the torque after getting home. I'm sure this has saved me a few times... Just to add, I also experienced the "swelling" lug nuts when I had an older Dodge Dakota. Luckily I caught them before they became too much of a problem and IIRC, I picked up a complete set of Dorman lug nuts to replace them all.

The plug and wire change is probably a smart idea. I'm at almost 69k and a 6 year old truck. I already know that the OEM 41-114 plugs are available at the local Oreillys so I will probably pick them up over the weekend. There is also a nice rebate available from Oreillys as well as AC Delco giving a $3 a plug rebate too. I checked on Amazon and know that I can get the OEM wires shipped to me in a day or so. This will give me a couple days before the trip to get it done. I do want to wait until after Monday and let the dealership change the one injector first and see how that goes.

Sorry, a little rant so ignore if you arent interested. And I was reminded again why I do not like some dealerships... It wasn't until this afternoon after not hearing back about the rental that is included in the GMPP plan that I called the dealership back. I was told that they contacted GMPP and was supposedly told that yes, I do have rental coverage but I would have to work that out on my own and submit the claim to be reimbursed. That didn't sound right so I called GMPP direct and was told that there are 3 options. First is that dealer provides a loaner. Second was that many dealerships have working relationships with car rental agencies like Enterprise, Hertz, etc. and they can arrange the rental and include the cost on the work order. Third is that I go out and get my own and pay for it myself and then file a claim for reimbursement. So I call the dealer back up and ask why I wasn't told about the first 2 options. I got somewhat of a runaround by the service writer and he wasn't really answering the question so I asked for a supervisor. The supervisor told me that this dealer used to maintain 10 rentals but because of a new vehicle shortage, they were forced to reduce it to 5. I can actually understand this and does make some sense. So then I asked about them dealing with rental car companies. He tried explaining that they don't have a working relationship with any rental companies because they are a small dealership and claimed something about their contract with Chevrolet won't allow them to do this anymore. This sounded like a BS answer. I asked him if he thought this was detrimental to his service department and a big inconvenience to customers and he said, "not at all" and went on to try and justify why. I said that providing a means for a loaner or a rental would go agreat deal towards customer satisfaction especially being able to include the rental on the work order. He completely disagreed and said that if I want a rental, they could call a rental company for me and have them call me to arrange the details and payment. So next I began to complain about the fact that my truck was going to be sitting there for the next 4 days because the parts aren't available until Monday. He said that my truck is still in the condition it was in when I dropped it off and is driveable and I can pick it up if I want to. 15 mins later I was there picking it up. Before I left, I had another conversation with the service writer. I'm kind of under the gun and am leaving town next Fri and want this handled before I leave. I asked him if he could guarantee that the part would be available on Mon and I bring the truck back and get it back by Mon afternoon. He said that could be done so I reluctantly agreed to be back first thing Mon morning. We shall see. But after this, I will be looking for another dealership that has a better idea of how to provide proper customer service.

Well the dealership called about an hour ago. They verified the P050D code as well as the P0301 code but they also got a P0300 as well. I was told that the tech found the problem and it was definitely the fuel injector for Cyl 1. I was told that it was stuck open. The bad news is that they won't be able to get a new one until Monday at the earliest. The service guy did say that the repairs will be covered under my GMPP but that usually, they normally recommend to replace all the injectors when this happens. However the GMPP will only authorize the injectors that are tested to be bad to be replaced. At least I still have a little over 50,000 miles and 3 years left on the plan for the rest to fail... At least there was no mention of any of the custom flashing that I had done with the Rough Country speedo calibrator so that's good.

Ruth roh!!! Well looks like I will probably find out tomorrow. Dropped it off at dealer tonight so they can do the cold start diagnosis first thing in the morning.

The misfires will peak about four times and then level off and stop. Rough idle while it's happening and when it stops, I get a smooth idle for the rest of the trip with no more misfires. But surprisingly, I only get the P0301 repeatedly and not a P0302.

I am using the Android version. It seems to work OK. I did have to add the predefined PID set for GM as the generic PID sensor monitors weren't all working. It's interesting to monitor things in real time like the coolant temp and see that the dash gauge is even more generic. The actual coolant temp can have a 20⁰ swing either way before the dash gauge moves off 210⁰. With Torque Pro, I know right away if temp is rising which has come in handy when pulling the toy hauler. I have found that the Trans Temp in the DIC is actually spot on and much better than the Coolant gauge. But I also like being able to monitor more stuff than the dash gives me. Plus the ability to clear codes to see if they come back up again. This is my most used real time screen for monitoring things. And this is one of the screens I have been using to check the misfires.

No I haven't tried that. I have seen that advice in several threads to diagnose it. The hard part is that this only happens at very first start when engine is cold. If I shut off and restart immediately, no misfires. So I would have to do the swap before the very first start otherwise I would gave to let it sit until the following day to retry. I figure I have the GM Protection Plan and already have the appointment for Thur so I will let them diagnose it first and see what they find. Just to follow up, I have regularly started getting the Torque Pro app and Bluetooth reader active before starting and 2 days ago, besides the code and also several misfires on Cyl 2, I now saw a bunch happening on Cyl's 6 and 8 as well. This lasts only for about 10 or 15 seconds on a cold start and results in a rough idle. It smooths out and then the misfires dont happen again until it sits for a long time, usually an overnight cool down. I keep it running while driving and never see any more activity. It runs just fine after the initial 15 seconds

Did you buy the truck used? If so, the previous owner took care of the initial recall. That would be why there are no recalls listed. As far as the recall, it was just flashing the software to update the pump operation with the false hope that this would solve the problem. In my case, the problem actually happened after the software flash. The Specual Coverage isn't a recall per se but is offering extended coverage to that component in case of a failure. The dealership won't do any fixes unless there is a problem. But if the problem happens, you should be GTG.

Not sure why yours wouldnt be included in the recall. As far as replacement of the brake booster, it was supposed to be for all 2015-2018 Silverados and Sierras at no charge as far as I was aware. It is Special Coverage N182202780 and is covered under this special warranty for 10 years/ 150,000 miles.

Quick update, I forgot on my Torque Pro app, I set up 1 of the screens to monitor current misfire conditions per cylinders. I put the key into run on a cold engine but didn't start it. I let Torque Pro connect to the reader first and then started the engine. It showed misfires on Cylinder 1 but, it peaked once and then smoothed out after the initial misfires. But it also showed many more misfires on Cylinder 2. This lasted about 20-30 seconds. It peaked several times and then smoothed out as well. Once it did, the idle was normal. Surprisingly, it didn't set a P0302 code along with the P0301 even though it seems there was a bigger misfire problem on Cylinder 2.

Looks like I will have an answer on this soon. Besides reverting back to stock programming, I pulled my Range AFM disabler so it has been fully stock for almost a month now. Yesterday when starting the truck, I had a very rough idle and almost immediately I got an advanced diagnostic alert to service emissions system from Onstar as well as the check engine light. A quick check on my reader shows a P0301 code now as well as a pending P050D again. Not happy because now I definitely need to get it in to the dealer. Especially because I am leaving town on the 16th dragging my toyhauler to Custer SD for several days and then on to Cody WY for a couple more days. I know the P0301 points to a cylinder 1 misfire. But I also know from the forum that it could be caused by a whole range of issues including fuel injector(s), bad coil, stuck lifter, among others. It gets dropped off next Wed night so they can do a diagnostic check first thing Thur morning. Bad thing is they don't have any loaner vehicles available until around the 16th. Fingers crossed that this is a simple fix and I can still take my trip...

Huh???