- #66 of 73
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1994 GMC Stalls
by mandobo
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Oct 15, 2009 (9:32 am)
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I have a 94 GMC pickup with the 5.7 litre engine. The problem I am having is that once in a while it just dies. If you try to restart it just cranks. I have to rotate the ignition switch to the off position the it will start then die. It runs a little longer each try until after about 10 to 15 mins. Then it runs fine for weeks of even months until it decides to do it again. Any Ideas would be greatly appreciated.
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- #67 of 73
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Re: 03 GMC SIERRA 4.8 STALLING [drake75]
by ndmech14
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Oct 28, 2009 (9:20 am)
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Replying to: drake75 (Nov 23, 2008 9:23 am)
I have the same problem with the stalling at a stop and low idle. It idles at around 400rpm when warm. It runs fine when cold. When I go from 15 mph to a stop it will stall about 50% of the time. The other times it will recover after the tach drops to almost "0". I have a 2001 Sierra 1500 with the 5.3 V8. I have done all of the following and the truck has shown no change in behavior.
1. Cleaned throttle bottle. It looks brand new.
2. Replaced IAC. Reset and drove for 1 month now.
3. Replaced fuel pump
4. Replaced fuel filter
Could it be fuel pressure regulator, vacuum hoses, bad ground?? I am almost out of money and need some help as well before I am completely broke.
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- #68 of 73
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Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
by pitstop1999
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Oct 28, 2009 (10:14 am)
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Replying to: ndmech14 (Oct 28, 2009 9:20 am)
Try your Catalytic Converters...engine light on? po420 or po430. Check fuel pressure. should be around 65 psi. so far I see you threw about 600-800 bucks in parts just take it to a mechanic. 85 bucks diognostic fee, if hes wrong get your money back.
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- #69 of 73
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Re: 03 GMC SIERRA 4.8 STALLING [pitstop1999]
by pitstop1999
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Oct 28, 2009 (10:18 am)
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Replying to: pitstop1999 (Oct 28, 2009 10:14 am)
Ohh ya intake maifold has been a problem in these trucks too. When they get warm the plastic intake expands causing an air leak. Try this to find out... when truck is warm and symptoms are there get a can of carb cleaner, brake cleaner , starting fluid and spray towards the intake area if engine idle increases or decreases thats your problem. oh BTY be careful. ( dont go wild spraying!)
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- #70 of 73
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Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
by jrutkis
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Oct 28, 2009 (11:58 am)
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Replying to: ndmech14 (Oct 28, 2009 9:20 am)
i acually found out that it might be your computer gone bad or a bad connection to your computer. i had the same problem and took it to my cousins shop. he ran diagnostics and found nothing so he made a few calls and said odds are its the computer. find out if your computer reset. if not thats prob your problem
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- #71 of 73
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Re: 03 GMC SIERRA 4.8 STALLING [pitstop1999]
by ndmech14
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Oct 29, 2009 (8:25 am)
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Replying to: pitstop1999 (Oct 28, 2009 10:14 am)
No engine lights at all. I had the shop run the diagnostic before I replaced the fuel pump and I was getting low pressure and they diagnosed it as a bad pump. I put in a new pump and that fixed the fuel pressure problem but not the stalling. I failed to mention that the line wasn't maintaining pressure before I replaced the pump. I would have to prime the pump about two or three times via the ignition before it would start. That problem went away with the new pump.
I have sprayed throtle bottle cleaner in the intake with the truck running at about 2000rpms and let it do its thing and it hasn't helped.
I reset the IAC by turning the ignition on for 30sec. Turning it off for 10 sec. Then starting it. I was told that was the way to do it.
I'll try resetting the computer again to see if that helps. I plan to unplug the negative and let it sit for about 10 minutes.
I haven't checked the regulator for gas yet, or done a pressure test on the vacuum system either. I might get around to that this weekend.
Anything else you guys can think of? I'll keep trying until it's fixed!
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- #72 of 73
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Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
by ndmech14
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Oct 29, 2009 (8:31 am)
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Replying to: ndmech14 (Oct 29, 2009 8:25 am)
Should I spray the brake cleaner around the intake manifold or by the coupler before the throttle body. Where does the leak happen in these instances? I assume I could just by some RTV sealant and reinstall the manifold with this at the seams to correct the problem?
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- #73 of 73
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Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
by obyone
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Oct 29, 2009 (8:44 pm)
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Replying to: ndmech14 (Oct 29, 2009 8:31 am)
The IAC needs to be removed and cleaned with an electric parts cleaner or better yet replaced. If the truck dies while moving that would be associated with the Throttle Position Sensor.
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