Mr. Tech...PLEASE HELP!

[TEE]

I have a 94 Silverado that I replaced the motor about one and a half years ago with a GM crate motor and added Edelbrock intake,shorty headers, and exhaust.

This motor has had a "stumble" at idle since day one and has really got me down.

Everything that can be thought of has been replaced with new including OEM EGR valve, IAC valve and all electrical parts with new.

The Edelbrock header location of the O2 sensor was on the drivers side bank only so I moved it back to the original posistion over the weekend thinking this could POSSIBLY be my problem but, to no avail.

Could it be a bad injector or evaporation canistor? Any thoughts and help will be GREATLY appreciated.

Worse case is I would have to take it to the dealer where I bought the engine and have it diagnosed....

Thanks,

TEE

[TEE]

Anyone?

[PaulieK]

Anyone?

 

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It only stumbles at idle???? How about thru the RPM band? Sounds like you have a cam that is a little over stock and that would give you a perceived stumble. I know the 402 BB I had built had what I thought was a very pronounced stumble but it was the racing cam with it's extended duration. Motor ran like a raped ape.

[TEE]

No it's a stock cam ( at least I don't think GM crate motors have anything other than stock).

What's even more confusing is when the A/C is on, it smooths out almost completely. It does run good BTW but, yes the small "stumbling" can be felt a little when you have it on a steady pull (like going uphill without making it kick out of OD)....not a miss just doesn't feel right.

Thanks