05 Silverado, Idle Issues, and some others

Keith Adams · May 16, 2020

I hope someone can help me to figure out the issues I am having with my 05 Silverado 2wd 4.8 vortec, 158,000 miles. I have owned this truck from day 1 and it has been a wonderful truck that has given me no problems. The issue I am having it engine surging at idle, and missing if I shut the engine off for a few minutes like to get gas. It cranks fine, runs great when cold, and as long as the RPM are at cruising range not a single issue. I spits and sputters when I leave the gas station or store after shutting it off and restarting it.

Here is what I have done so far

1. New Delco Knock sensors,

2. New intake gaskets, o-rings for fuel injectors and fuel rail

3. New MAF Sensor

4. Clean Throttle Body

5. AC Delco Spark Plugs, Delco Wires

6. Checked fuel pressure 58psi

7. The only code I am getting is misfire.

Have an idea what it might be or what else I can try?

Jstevens7700 · May 16, 2020

Might want to either test or replace the ignition coil packs. That's what it sounds like to me when you say the truck is running bad after a few minutes of running. Are you getting a cylinder specific misfire code or a random multiple misfire code?

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Keith Adams · May 17, 2020

Thank you for the reply, I had not thought about that. I will look at this and see if this is where the problem is.

Jstevens7700 · May 17, 2020

Yeah with that milage it might be time for a set.

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Joseph Billeter · May 25, 2020

Try relearning throttle position sensor before doing anything else, just YouTube it it’s so fast.

tlaw91 · May 25, 2020

Do NOT replace the coils. They never go bad that’s a waste of money.

Did you try and remove the purge valve and plug the hole to see if the purge valve is hanging open?

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Joseph Billeter · July 31, 2020

You ever actually figure this out? My problem was right behind yours! I replaced my throttle body being pretty damn confident it was that. I have no codes though, I replaced basically all of my evap system within the last year too, found a cracked pcv hose... yea not the issue. A couple other small things but I don’t want to keep hunting at this point.