[Zillon]

Usually, upon startup, when I go to pull away from the curb, the engine stumbles a little and nearly stalls.

I know that I need to replace the gasket between the throttle body and intake plenum, but wouldn't that cause a surging idle and not what seems to be an air starvation problem?

I just replaced the fuel filter, air filter (K&N) was just recharged, intake was cleaned out thoroughly when the valvecover gaskets were replaced, EGR was replaced and tube cleaned, O2 sensor has less than 5k on it, and I also recently did a complete seafoam run-though (engine, oil, and fuel) to clean out everything.

Also, if I am sitting still after startup, and I rev the engine to around 3500-4k, and let off, it will also stumble. I have gotten it to stall out completely once because of this.

Would anyone know what might be causing this problem? Fuel pressure regulator? Fuel pump?

 

[JTK]

Zach- this could be the gasket leak you speak of, as the hi amount of vacuum generated at idle could cause the leak to be worse, but more so than that, I'd say your idle air control valve (IAC) is sticking or shot. It's bolted to the throttle body right near the throttle.
G/luck
Joel

 

[Zillon]

Thanks, I'll have to give that a check. Anything else that it could possibly be?