Last post on Sep 18, 2013 at 2:32 PM
You are in the Chevrolet Silverado & GMC Sierra
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GMC Sierra 1500, Truck
#67 of 151 Re: 03 GMC SIERRA 4.8 STALLING [drake75]
Oct 28, 2009 (9:20 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.
#68 of 151 Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
Oct 28, 2009 (10:14 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.
#69 of 151 Re: 03 GMC SIERRA 4.8 STALLING [pitstop1999]
Oct 28, 2009 (10:18 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!)
#70 of 151 Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
Oct 28, 2009 (11:58 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
#71 of 151 Re: 03 GMC SIERRA 4.8 STALLING [pitstop1999]
Oct 29, 2009 (8:25 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!
#72 of 151 Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
Oct 29, 2009 (8:31 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?
#73 of 151 Re: 03 GMC SIERRA 4.8 STALLING [ndmech14]
Oct 29, 2009 (8:44 pm)
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.
#74 of 151 Re: Stalling 2500HD 6.0 silverado [chevellessman]
Jan 13, 2010 (5:31 pm)
I have a03 sliverado 5.3 it stalls and dies sometimes when I stop or slow to turn. It starts back up like nothings wrong,but happening more often. Does anyone have an answer for this problem Also the service engine light has not came on.I have a new battery and had the alternator checked and it was ok.
#75 of 151 stalling sliverado
Jan 13, 2010 (5:32 pm)
#76 of 151 Re: Stalling 2500HD 6.0 silverado [fishsalot2]
Jan 13, 2010 (5:43 pm)
I posted a while ago and had replaced several items. Turns out nothing worked because my replacement iac was the wrong model #. Put the right one in and it no longer stalls. I also thoroughly cleaned the throttle body with throttle body cleaner. If doing those two things didn't fix your problem for this particular problem, I'd be shocked. This truck is known for its throttle body issues.