Jump to content

1999

rjgti

Recommended Posts

rjgti Enthusiast

rjgti

Posted
Posted

truck started running rough tonight. stalled 2 times. cannot hear fuel pump at all anymore. has whined for 6 years. will put a gaguge on it tomorrow. what is rail psi. 70 psi. what is leakdown when shut off? strange i just cleaned and reoiled my air filtler. drove 400 km without a problem. started truck and when i get on the gas it hesitates and misfires. not bad enough to light a code. i've done this airfilter 10 times with no problem, i took air filter of and inspected it and there is no sign of over oiling. just starting to sink my teeth into this. any ideas?

mr_bots Enthusiast

mr_bots

Posted
Posted

Since it's an oil air filter, might try cleaning the MAF, if it's dirty it can make it run and act really weird.

08SGMSierra Enthusiast

08SGMSierra

Posted
Posted
truck started running rough tonight. stalled 2 times. cannot hear fuel pump at all anymore. has whined for 6 years. will put a gaguge on it tomorrow. what is rail psi. 70 psi. what is leakdown when shut off? strange i just cleaned and reoiled my air filtler. drove 400 km without a problem. started truck and when i get on the gas it hesitates and misfires. not bad enough to light a code. i've done this airfilter 10 times with no problem, i took air filter of and inspected it and there is no sign of over oiling. just starting to sink my teeth into this. any ideas?

 

If you FP is not longer making noise I would start there. Also, when was the last time you checked/replaced your plugs/wires? I had a similar problem this winter with my 95 Caprice. Sometimes it would run fine, then it would darn near shut off for a second, then kick in. Some of my plugs were bad, and a few wires were iffy. That solved it, runs good as new now.

 

HTH.

08SGMSierra Enthusiast

08SGMSierra

Posted
Posted

Wanted to add my co-worker has a 99 LS Silverado and he just turned 100k. He has all kinds of driveability issues and it took the dealer several tries to correct it. He had a bad ground, plugs/wires, and I believe a fuel problem as well.

rjgti Enthusiast

rjgti

Posted
  • Author
Posted

anyone know what the fuel rail pressure should be? is it 70 psi. will be measuring after work today. and i've never heard of cleaning a mass air flow sensor, when they become contaminated they are finished. plugs and wires are good.

pennzoil29 Senior Enthusiast

pennzoil29

Posted
Posted
anyone know what the fuel rail pressure should be? is it 70 psi. will be measuring after work today. and i've never heard of cleaning a mass air flow sensor, when they become contaminated they are finished. plugs and wires are good.

 

CRC makes a good cleaner. Follow the directions on the can.

rjgti Enthusiast

rjgti

Posted
  • Author
Posted

i will have to search for crc. do you remove and spray air meter edit: just google crc and no hits for cleaner.

Lincoln30 Enthusiast

Lincoln30

Posted
Posted

If your truck is starting on the same number of cranks as it did before it started running rough then your shutoff fuel pressure is fine. If that pressure drops below where it should be your truck will crank a lot more before it will start. I think 59-62psi is correct???

 

I'm in the "clean the MAF camp" on this problem. I've always done it with a q-tip and alcohol but the spray seems like a safer (but more expensive) way to accomplish the task. It's cheap and easy to try this before you tackle plugs/wires and the fuel pump.

rjgti Enthusiast

rjgti

Posted
  • Author
Posted

i'm thinking mass air meter. since i did just oil filter. maybe goofed this time and over oiled, but 400 km till problems. hmm.

Jug Enthusiast

Jug

Posted
Posted

Might be dumb, but could it be water in the gas? Maybe some fuel treatment or similar? Just a thought.

08SGMSierra Enthusiast

08SGMSierra

Posted
Posted
Might be dumb, but could it be water in the gas? Maybe some fuel treatment or similar? Just a thought.

 

Not a bad idea. Also, may want to consider fuel filter. My mechanic recommended doing it once a year as he has seen a lot of bad gas around here.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • Atlas
      Gas Prices

      By Atlas · Posted

      Those can be high, as well as the big California cities. The ones that will pop your eyes out are the 395 corridor on the Eastern side of the Sierra Nevadas. Lee Vining, $7.19 for regular and $8.89 for diesel is what the Google said right now.
    • newdude
      2020 Trailboss 6.2 replacement

      By newdude · Posted

      Correct.  2019-2021 model years are serviced by a different p/n.  19420611.  Recall 2021s use 19420611.   The recall engines 2022-2024 model years are serviced with 12740076.     The difference between 19420611 and 12740076 is GM changed injector size for 2022.  The injectors are smaller on 12740076 with smaller injector bores in the cylinder heads to match the smaller injectors.  So you can't install a 19420611 in a 2022-2024, and you can't install a 12740076 in a 2019-2021.     Both engines are the replacement engine p/ns that are in the L87 recall.  So both of these are the updated engines.     Here's a version of the L87 recall with the p/ns for all the parts needed.    RCRIT-25V274-7075.pdf   Note it shows 19420611 and 12740076 with an asterisk to a footnote "Use the VIN and the GM Electronic Parts Catalog (EPC) to determine which part to order if two or more part numbers are listed for the same part, as it may vary by vehicle options."    
    • 2017Z
      2020 Trailboss 6.2 replacement

      By 2017Z · Posted

      Looking for advice from this group. Took my flawless 2020 6.2 TB to an unnamed shop for routine rear brakes and oil change. Tech forgot to put oil back in after the full service and needles to say, destroyed my engine.  It’s all on their shop video so they are responsible.   I had my Chevy dealer do the analysis and they confirmed its compromised and said engine replacement. The manager said they only get GM reman engines from GM with full 3 yr warranty and the one they would put in is not same as what’s they are swapping out on 21-25 for recall.    I am looking for advice why that would be a different engine because obviously I had the good 6.2 year and replacing it has my concerns with that recall for 21-15   Also what’s the pros and cons of accepting the engine swap vs telling the shop that bricked the truck to pay up so I buy a new truck. I’m concerned about stigma resale eventually if I just decide to get rid of it after the swap or other issues showing up after the swap out.  
    • GN2018
      AFM Disabler Question

      By GN2018 · Posted

      Just looked up my records.  I've never gone over 5000 miles between oil changes.  At 46K miles, I have 10 oil changes.  I hope that will help.  I also installed the disabler last year.  I've still had a few times when it didn't seem to engage (which I can tell because the start stop feature kicks in), but for the most part, I think it's working.  For some reason, GM did not include the number of cylinders running in the information screen like I had on other models.  In my Cadillac, it shows me when it's running on 4 cylinders on the fuel milage screen.  I can't find that on my '21 Denali.
    • davester
      Wiring Help, Please

      By davester · Posted

      you might read through the info on gmupfitter.com for your truck, to find a good power source.

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...