3.4 DOHC rough warm idle

[White93z34]

this one has been bothering me for a little while now, and the cars done it since I bought it.

 

It will idle rather rough after its warmed up. I had my plenum off last night, All my injectors ohmed out to aprox 12.7 ohms.

 

When It is cold, it idles perfectly smooth. EGR is disabled in the PCM.

 

I put brand new delco plugs in it when I put the new trans in it, also put the delco wires off my old 3.4 in it as the ones on it were kinda sliced up.

 

could this be just a simple matter of seafoaming it, or maybe replacing my coils?

[Crazy K]

do a spark check on each coil and wire.

[GOT2B GM]

How does it idle when say, you engage the A/C compressor at idle when its warm.

 

My Z has a kinda "lopey" idle only at warm as well. But smooths right out if you turn the A/C on.

[Schurkey]

When my '92 did that, it was the intake gaskets. The gaskets have a silicone seal around the ports, mine were abraded and cut. Apparently, from relative movement of the intake manifold against the head as the engine warmed up.

 

Common problem with GM vehicles using that style of intake gasket. The aftermarket gaskets--and probably the OEM GM units available today--are better.

[White93z34]

I know its not that, the car had new intake gaskets on it when I got it, and I ended up redoing the intake gasket job after I broke the heater core fitting off and had to remove the lim to fix the problem. So I can rule that much out.

 

I haven't drove the car but 15 miles in the past week. I'll have to let it get warmed up again soon and see what I can observe.

[GP1138]

How's the fuel filter?

[Drummer]

mine does the exact same thing sounds like it's missing every once in a while at idle until you turn the a/c on, and i've changed plugs, wires, coils, and cps. Mabye it's just a 5 speed thing

[GOT2B GM]

Maybe it's just a 5 speed thing

 

I seriously wouldn't doubt it.

[White93z34]

How's the fuel filter?

 

Brand new when I put the car together, so that means aprox 3000 miles.