GMC Troubleshooting Questions? Ask a Mechanic for Answers
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When does it stall?
Do you have a security light?
Do you have test equipment?
Do you have a scanner? Is this a Jimmy?
Do you have a scanner?
Do you have a fuel pressure gauge? test light?
The 5.7 fuel pressure gauge goes where the fuel filter goes. You remove filter and it has hoses to hook up to lines.
Lets look at something else first though. Make sure your under dash connector is 12 pins first. If its not 12 pins dont do this.
Can you cross the top 2 pins on your DLC connector. Turn key on and count the check engine light flashes. It should flash 1 and 2 flashes 3 times and then flash any codes.
Also when is the last time you changed the fuel filter?
My immediate suspicion is the fuel pump
All of your symptoms point to a fuel pump. I would check fuel pressure
I would check fuel pressure. Make sure it holds the pressure
What is the pressure?
There are a few things to look for:
1. You could have egr valve slightly open
2. Vacuum leak
3. Tps sensor fault.
I am still suspicious of fuel pump. I dont know how you had it checked
there are several symptoms of a fuel pump. You can have low pressure, low volume and not holding pressure once built. Checking pressure is only part of the test. did you check the regulator is working when checking pressure? Like I said I dont know how you checked and am trying to assist you. Checking and saying it is good is very vague. I need more information
I would not want you not happy. So I am going to opt out and see if someone else can assist.
Hi, My name is ***** ***** for the delay.
I will do my best to assist you
does the truck run well out on the road?
at wide open throttle does the truck pull well?
ok..lets try something,,remove the vacuum line from the egr valve and plug it with a scew or something,,then drive it,,,did that fix the idle problem?
i dont think the problem is the fuel pump sense it does run well out on the road