I have 1500miles on this new engine mild cam, 2 1/2"exhaust no cat full headers,1991 TPI, al heads,730 ECM SD. My problem is that it hunts for a stady idle (700-1000 rpm) from start up until it reaches 190 degrees. After it gets to operating temp it runs smooth and idles at 590-600. Any help on what could be wrong please help. thank you Mike

 

Is it slightly rich when cold and proper air fuel when warm? Idle seems to stabilize for me when I lean out and add timing.

Does the chip pull timing when cold? I would think you would want abit more

 

IMO, many hunting idles are from vacuum leaks. You say yours stops at 190*. Could it be that idle stabilizes because a vacuum line somewhere in the engine compartment might have a small crack or slit at its connection point that is slightly open when cold (ambient), but closes when heated? Might be worth a vacuum test.

 

yes it is a little rich about 11-13 it starts out at 11 and slowly climbs until closed loop. I'm going to get a can of carb cleaner and look for a vacuum leak.thanks for your help Mike