i have an 87 firebird lg4 auto quadrajet only mods are open element and emissions delete. the car runs and drives pretty much perfect when cold until it is driven a little bit (i assume when it goes into closed loop). then it will start bogging down and die at idle and very light throttle, i suspect it is flooding out. but as long as i give it gas at idle it still drives pretty much perfect.

second issue i am having which im 90% sure is related to the first is after it dies from not being able to idle the carb floods the throttle plates with fuel until the bowl and (aftermarket inline) filter are drained. but it only does it if the car was starting to die from issue number one. i can start and shut down cold and not have issue #2.

i have taken the carb apart and rebuilt it 4 or 5 times and still cant find out the problem. i am also getting a code 23 for the mcs. i suspect it has went bad but it wouldn't explain issue #2 would it? i could really use some help this is my first time messing with a carb ever and i don't know anyone local the knows anything at all about these cc quadrajets.

 

You're correct that one issue is probably related to the other. And no, a shot MCS wouldn't cause fuel to spill out of the boosters.

Fuel pressure too high, float level too high, float is shot (losing buoyancy), inlet valve shot/leaking/dirt in it. Those are your usual suspects.

 

by the inlet valve you mean the seat and needle correct? and ill go pick up a fuel pressure tester and new float tomorrow.