Okay today I helped my friend pull of all the emmissions control stuff off his 84 Z-28, that has an L-69. We pulled the air pump, all the tubing connected to it, and plugged the holes on theexhaust manifolds for those metal lines. We plugged off all the outlets on the carb that were no longer needed. We started up the car and it wouldn't idle right. My friend said it was idling higher than usual and the car stalled as soon as he put it in gear. Once he got it to stay running, we drove around the block a couple of times and the car would idle just fine. Assuming his car is tuned right(which I doubt), and there are no vacuum leaks, what would cause this idle problem that goes away after a little driving? Sorry this was so long.

 

Ok... I see one problem... you are assuming too much... I would say that the A/F mixture needs to be adjusted since you removed the backpressure (provided by the cat). I'm not sure whether you would be running rich or lean, but adjust the mixture until it runs right or you can be sure that it isn't the mixture. I would be surprised if it didn't need tuning after taking out the cat. Start out by trying to richen it, it should increase the idle...

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1984 Firebird - Daily driver, 305 LG4, T5 - Hurst short shifter, Edelbrock 600 CFM Performer Carb - Edelbrock Pro-Flow air filter, gutted cat, IROC 16x8 Wheels, Goodyear P215/60/R16, AIWA bargain basement (from Sears of course) CD player
Check out my ride here

Quote from my sister: "It sounds like a boat"

 

Whoops-my bad. I should've wrote that we removed all the emmissions stuff thats under the hood. Air pump, those miles of vacuum lines, etc. We didn't touch the cat cuz its pretty new but we did cut the tube that goes to the cat and sealed it off. Could a bad seal have something to do with the problem? I also remebered something else. He didn't end up removing the EGR valve because he couldn't find a blockoff plate. He may have forgotten to plug the ports on there. Does this sound right?