Hello all,
I have a 1989 Firebird, 305, TBI, VIN Code E, with Calif emissions. I have a question about the idle, I've been haveing problems with the idle rpm. Its seems to be erratic. I can be driving down the road and let off the gas and still have high idle, I put the car in neutral and I have 1500 rpm. Next I replaced the IAC valve and adjusted it with no luck. So I put the ECM in diag. mode which extened the IAC and disconnted the connection, takeing the IAC out of the TBI. I am still haveing problems, its weird, when driving the RPM is ok, when I left off the gas it still has high rpm then I step on the acceraltor and then the idle goes to normal. Its like haveing an a spring choke. I have no idea whats going on here, I have no error codes, and the car runs like a champ. All and any information will be greatly appreciated.

Brad
San Deigo

 

is the return spring on the linkage or cable working ok, no binding? throttle blades not binding up, timing ok?

 

Timing is ok, will look at springs and butterfly blades. Do you think it might be the TPS?

 

would be something to look at, i doubt it, but i'm not that good with the ecm stuff. check it, or reset it and you'll know for sure.

 

timing ok, springs ok, linkage ok, TPS is ok..everything checks out. any other ideas, anybody

 

Check for a vacuum leak. Mine was the intake manifold gasket. Erratic idling, loping, not to mention the oil seepage.