Sitting here waiting for a tow truck.

1kwik72 · January 17, 2014

The trucks are designed in Michigan, you think they would factor in cold weather testing when they are engineered...

They are, but after 25 years of wrenching on vehicles I can tell you they don't always fail the way the engineers think they will. Nor do things behave out in the real world like they do in simulation or even durability testing. If they start to see pattern failures (there are a few already being identified on these trucks) they will tweak the design/software/manufacturing process to eliminate the issue. Like it or not we are sort of the guinea pigs in a first year vehicle. They will probably have some bugs lets just hope they are minor as they should have worked the big stuff out.

You mentioned your dealer called did they come up with anything?

Craig

fondupot · January 17, 2014

Update from post 15. Sorry I posted to quick in that one.

They said that the reason the check engine light came on and the loss
of power occurred was due to a misfire on two cylinders. She said GM
has issued a service bulletin to check the spark plug wires to make sure
they are attached correctly. She said that the technician didn't find
any loose wires. But the truck was ready for pickup.

She then was saying that the misfires were nothing to be concerned about
and that it happens on occasion. So I asked her what would cause a
misfire if the spark plug wires were not loose? She couldn't answer
that. This is when I got a little upset. I told her that its not
acceptable to just say the truck had some misfires and that everything
is fine now. Something obviously caused the misfires, and it shouldn't
be happening on a new vehicle.

I then spoke with the service manager and told him that I want them
to investigate the issue with the truck further. I said, its more of a
safety concern, since this misfire and loss of power happened in the
middle of traffic and I nearly caused and accident trying to get out of
the way with the pedal floored but the truck just wouldn't move.

Service manager agreed and said they will keep the truck longer and
hook it up to their test equipment and investigate it further while
putting some miles on the truck.

I guess that's better, but I am still a little miffed that they were just going to brush it off that easily.

Oh and while they were at it they reprogrammed the computer for the Fire Risk recall.

Gonna keep the loaner over the weekend and the service manager said he will call me on Monday.

cool.

GMC-AT · January 17, 2014

The issue is you will have a lack of confidence in your truck.. until they can tell you 110% what was wrong..

mike94silverado · January 17, 2014

Hope they check it out.... Driving around worried about your vehicle sucks especially when its new....

1kwik72 · January 17, 2014

I just saw your edited post. I went back in GMesi and looked because I thought I saw a couple PI (Preliminary Information) relating to misfires. One was the loose spark plug wire one. The other one had to do with water and corrosion in the coil connector. I am sure they would check the coils on the affected cylinder but who knows. I thought I remember seeing something about the wiring harness under the intake having issues on early built trucks too but my memory could be wrong as I don't see it in esi

Craig

mike94silverado · January 17, 2014

i keep hearing "cold weather" as an excuse from dealers. i mean is this the first winter it's ever gotten cold out there? come on.

My dad has been getting this same BS from the dealer about his 2011... it's showing all signs of a TPS problem but they keep saying everything from winter fuel to his remote start (that they Installed) causing it..... about ready to bring it elsewhere, but I figured if it was something with the starter (Doubtful) it's their problem anyways

fondupot · January 17, 2014

So I dont know if this would cause a problem, but I recently filled up with Shell V-Power 93 octane (10% ethanol in illinois). Normally i use Shell 87, but I wanted to see if there was a difference in mileage with the 93 octane. I read that the computer will adjust for the added octane. But I've never heard of too much octane causing misfires, only not enough octane. Any thoughts on that?

Hope they check it out.... Driving around worried about your vehicle sucks especially when its new....

Exactly. Its BS.

The issue is you will have a lack of confidence in your truck.. until they can tell you 110% what was wrong..

100% agree.

I just saw your edited post. I went back in GMesi and looked because I thought I saw a couple PI (Preliminary Information) relating to misfires. One was the loose spark plug wire one. The other one had to do with water and corrosion in the coil connector. I am sure they would check the coils on the affected cylinder but who knows. I thought I remember seeing something about the wiring harness under the intake having issues on early built trucks too but my memory could be wrong as I don't see it in esi

Craig

What is GMesi? I'd like to check that out. I remember reading about some people having issues with misfires and coils on here but I cant find the posts (they are in that massive thread about "having problems with your 2014") And for some reason the search function sucks on this site.

My dad has been getting this same BS from the dealer about his 2011... it's showing all signs of a TPS problem but they keep saying everything from winter fuel to his remote start (that they Installed) causing it..... about ready to bring it elsewhere, but I figured if it was something with the starter (Doubtful) it's their problem anyways

The TPS is a pretty inexpensive part. If you suspect its bad. Might just replace it yourself and see if it helps your dads truck any.

DanMan_S · January 17, 2014

I just saw your edited post. I went back in GMesi and looked because I thought I saw a couple PI (Preliminary Information) relating to misfires. One was the loose spark plug wire one. The other one had to do with water and corrosion in the coil connector. I am sure they would check the coils on the affected cylinder but who knows. I thought I remember seeing something about the wiring harness under the intake having issues on early built trucks too but my memory could be wrong as I don't see it in esi

Craig

I had this issue on my 2009. Kept getting misfire warnings and reduced power/stability control/traction control errors. Turned out to be a bad plug wire. The clip had failed so the plug wire wouldn't stay on the coil, would slide off, and fill with moisture. Would always give problems after it rained or snowed, then would go away after the truck warmed up.

I initially fixed it by cleaning the coil and the plug wire out, and filling with dielectric grease. And permanently fixed with some new plug wires and new spark plugs.

fondupot · January 17, 2014

I had this issue on my 2009. Kept getting misfire warnings and reduced power/stability control/traction control errors. Turned out to be a bad plug wire. The clip had failed so the plug wire wouldn't stay on the coil, would slide off, and fill with moisture. Would always give problems after it rained or snowed, then would go away after the truck warmed up.

I initially fixed it by cleaning the coil and the plug wire out, and filling with dielectric grease. And permanently fixed with some new plug wires and new spark plugs.

Like, why wouldn't the dealer just replace the plug wires on the cylinders that misfired. This would be my initial reaction if I was diagnosing the problem myself....seems logical.

DanMan_S · January 17, 2014

Like, why wouldn't the dealer just replace the plug wires on the cylinders that misfired. This would be my initial reaction if I was diagnosing the problem myself....seems logical.

Truck was out of warranty so definitely wasn't bringing it back to the dealership. Heck, even when it was under warranty I did most of the maintenance myself.

And with the plug wire replacement, I'd driven the truck for 100000 km with headers on it....the factory plug wires were in bad enough shape as is (too much close contact with the headers had cooked 'em) and I was planning on replacing them anyhow with some MSD wires with header socks. Figured if I needed to replace one, might as well do the set.

1kwik72 · January 17, 2014

GMesi is GM electronic service information. It is the actual service manuals technical service bulletins and information in electronic format. And I bet you would like to check it out. at my discounted rate for being a ACDelco Professional Service Center it is $1200 a year.

Yes your higher octane could have been the cause also if it did it when it was cold. The easiest way to explain octane is to think of it as the higher the number the harder it is to light the fuel. In cold weather they change the volatility of the fuel to make it easier to burn (more light ends of the hydrocarbons making it more volatile). Higher octanes on average will be harder to start burning. They can fail to light under the right (very cold) circumstances. My supercharged Grand Prix normally runs on premium (recommended but not required) and it picks up about 3 mpg over 87 but this winter it did not like to start on 93 so back to 87 and it starts and runs great in the cold. The other thing is premium fuels tent not to move as fast as lower octanes so if there was any water contamination ( snow melt seeping past the gas station tank fill cap) generally the higher octanes are more susceptible.

Craig

1kwik72 · January 17, 2014

I had this issue on my 2009. Kept getting misfire warnings and reduced power/stability control/traction control errors. Turned out to be a bad plug wire. The clip had failed so the plug wire wouldn't stay on the coil, would slide off, and fill with moisture. Would always give problems after it rained or snowed, then would go away after the truck warmed up.

I initially fixed it by cleaning the coil and the plug wire out, and filling with dielectric grease. And permanently fixed with some new plug wires and new spark plugs.

The first bulletin does address the spark plug wires and says if they do not "click" when you install them to replace them.

The second bulletin regarding the water intrusion is on the primary side of the coil in the weatherpac connector. The fix is to clean/replace the affected component (coil) and connector if needed and apply dielectric grease.

Craig

fondupot · January 17, 2014

GMesi is GM electronic service information. It is the actual service manuals technical service bulletins and information in electronic format. And I bet you would like to check it out. at my discounted rate for being a ACDelco Professional Service Center it is $1200 a year.

Yes your higher octane could have been the cause also if it did it when it was cold. The easiest way to explain octane is to think of it as the higher the number the harder it is to light the fuel. In cold weather they change the volatility of the fuel to make it easier to burn (more light ends of the hydrocarbons making it more volatile). Higher octanes on average will be harder to start burning. They can fail to light under the right (very cold) circumstances. My supercharged Grand Prix normally runs on premium (recommended but not required) and it picks up about 3 mpg over 87 but this winter it did not like to start on 93 so back to 87 and it starts and runs great in the cold. The other thing is premium fuels tent not to move as fast as lower octanes so if there was any water contamination ( snow melt seeping past the gas station tank fill cap) generally the higher octanes are more susceptible.

Craig

Thats interesting. I have probably 3/4 of a tank full of 93 octane. I guess when I get it back i'll be sure to keep using 87. Also, its not like it was super cold out today, it was about 13 degrees. And my truck parks in a heated garage overnight, so it warmed up pretty fast. I've used this same gas station for over 2 years and never had a problem with the gas from it....

Hopefully it was just a bad wire and not due to 93 octane.

1kwik72 · January 17, 2014

In a heated garage I would doubt you would have an issue. 13° outside yeah it wouldn't surprise me one bit having issues. Bad gas isn't as prevalent as everyone would think but it does happen every once in a while.

What you are dealing (an intermittent) with is a pain in the A$$ for both you and the shop working on it. Trust me from my time being on the other side of the counter they would like nothing better than to tell you exactly what went wrong and get paid to fix it. The issue is once the tech starts disconnecting things checking stuff out sometimes it "fixes" the poor connection and the problem goes away. Did they actually fix anything... not really but at the same time they cant fix it if it isn't acting up. Its a balancing act with something like that you either keep the car attempting to duplicate the issue (which rubs some customers wrong) or you give it back to them while explaining as best you can what steps you took and what you found. Dealerships usually aren't the greatest at communication unless you push the issue. I try and educate my customers so when the problem comes back they will come back to give me another chance at trying to catch it in the act vs being pissed I didn't fix anything the first time around.

Craig

fondupot · January 17, 2014

In a heated garage I would doubt you would have an issue. 13° outside yeah it wouldn't surprise me one bit having issues. Bad gas isn't as prevalent as everyone would think but it does happen every once in a while.

What you are dealing (an intermittent) with is a pain in the A$$ for both you and the shop working on it. Trust me from my time being on the other side of the counter they would like nothing better than to tell you exactly what went wrong and get paid to fix it. The issue is once the tech starts disconnecting things checking stuff out sometimes it "fixes" the poor connection and the problem goes away. Did they actually fix anything... not really but at the same time they cant fix it if it isn't acting up. Its a balancing act with something like that you either keep the car attempting to duplicate the issue (which rubs some customers wrong) or you give it back to them while explaining as best you can what steps you took and what you found. Dealerships usually aren't the greatest at communication unless you push the issue. I try and educate my customers so when the problem comes back they will come back to give me another chance at trying to catch it in the act vs being pissed I didn't fix anything the first time around.

Craig

Thanks Craig. I understand where you are coming from. I guess all I can do now is wait til next week and see what they discover from further diagnosis.