1995 Chevy K1500 5.7L--- EGR Issue

Now I have seen multiple posts on the EGR valve and I have symptoms of a EGR problem however mine seems to be a little unique. I do know when my ECU requests for the EGR to open it does and the valve opens. The EGR solenoid and the Valve seems to be working just fine.

If i disconnect the vacuum line to the EGR my truck runs smooth throughout all ranges of load. Idle on up. So I know its and EGR system problem. If the EGR is connected i get stuttering at rpms just slightly higher than idle.

My question is when should the EGR be open. On my truck my diagnostics scanner it shows to be closed ONLY when at idle. If I start from idle and press the gas the egr will immediately pick up opening the valve and cause stumbling ...until I reach approx 2k to

3k rpm in which it seems as though the engine will smooth out( EGR still open though). Why does my truck request the EGR to be open right away. It seems like it is suffocating the engine at such low loads.

I am beginning to think that my ECU or an input to the ECU is gone bad, which is causing it to pre-maturely request for opening.

Anyone have things I could check or other posts to read. However, like i said before its seems like its not the common EGR solenoid or valve stuck open.

Reply to
Curt T Johnson
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Does it stumble when cold? My guess is its ignition related. Cheers

Reply to
Martin Riddle

No it does not stumble when cold. Apparently when cold the ECU wont send a signal telling the EGR valve to open. As soon as it reaches operating temperature the problems will start happening

Reply to
Curt T Johnson

Sure sounds like a lean miss then. But I would double check the ignition system, then hoses for cracks, then for a manifold tbi gasket leak, then a manifold leak.

Cheers

Reply to
Martin Riddle

Not trying to revive a 8 year old thread but I have a question for the original poster since I have the exact same issues down to the letter of your posting did you fix the problem and if so can you tell me what ended up being the issue so I can fix my 95 k1500 without playing the "maybe" or "try replacing" game of forum answers.

Reply to
Shane Thompson

Ignition problem? That what mine turned out to be, a corroded pickup coil. It's been a rough winter, so you should take a peek.

Cheers

Reply to
Martin Riddle

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