First of all I have a '94 Z28, it starts slow almost everytime I start it, sounding like it may be high in time, havent checked it yet. But thats not the real problem, when you first start it, the idle will jump to around 2000-2500 and hold there. Drop it in gear and the idle will bounce up and down excessively or may stall if it drops too low... Seems like its running too rich then, it black smokes sometimes when that happens. But if I get it moving, in about 10-15 seconds it will quit acting up and run fine... Already changed the coolant sensor, and the MAF is descreened if that makes a difference, bypassed TB coolant and CAI... Though I am only getting 12mpg but that may have something to do with the tranny being stuck in limp mode, but thats another post... Anyone heard of this idle problem??

 

sounds like an opti issue to me me bud sorry

 

could be sticky iac motor, maf, intake air temp sensor, throttle position sensor or the dreaded opti. have u had it scanned for trouble codes?

 

Had it scanned a month or two back when I started putting tranny solenoids in, I believe it had two tranny codes, an EGR code and a MAF. But I think I had tried unplugging the MAF to see if it was the problem. Also the SES light would never stay on, it would come on and go off as it pleased around the time I had it scanned. Now its staying on though... EGR maybe? Might have it scanned tomorrow to see whats new in there...

 

i think a bad egr will do it and may need changed. wouild be best to get it scanned to get an idea what it points to.