I just purchased an L69 with 71k original miles which was kept completely stock and well mantained. The engine idles around 1250-1400 rpm's, when cold or warm. Also, when I accelerate I can hear a slight "popping" sound. The car runs strong and throttle response is fairly good. No codes are showing and the ECM is functioning as it should. Sound like just a vaccuum leak or something more in depth?

 

check for vacuum leaks and make sure that the choke is coming off when the motor is warmed up. Sounds like it's sitting on the high idle cam stop and not coming off it possibly.

 

I agree.... check to see that the choke is opening once the engine warms a little bit, and that the fast idle cam is coming off. Check to see that the power wire to the choke is also connected and supplying power. It sounds like a possible choke problem.

 

Thanks guys. I will check that out. I'll let you know how it works out.

 

Today was a nice day here in NY so I pulled the Z out of the garage to check the choke. The choke opens as it should after it warms up but the idle is still around 1250-1400 rpms. No codes and no choke light. All the other F-bodies I owned were TPI and MFI(LT1) so this carb thing is new to me. I'm not familiar with the high idle cam stop.

 

some pics

 

Sounds to me it's backfiring. Are you getting enough air or maybe too much? With it idling that high, you may be flooding it. Check your spark plugs to make sure they're gapped in unison and at the proper spacing. I prefer .45 for most engines. Make sure your timing is correct.