strange engine issue from 900-1400 rpm

[Bocephus69]

Originally Posted by Redline novdog

If it were me would pull the carb off and run some tag wire through all the passages and blow air through afterwards. Check your primary throttle shaft for play(worn) also.

this shaft has play. i ran the engine and sprayed carb cleaner on the passenger side (where the roll pin goes trough the shaft to hold it in), and i do get a slight rpm change. it is barely noticeable, but no doubt it is sucking in a little air there.

[swamp rat]

Remove the air cleaner (engine off) then pull one of the air fuel screws all the way out and take a can of carb cleaner with the spray nozzle and stick it in the hole till it bottoms out, open the chope plate and throttle plate and look down the carb, give the carb cleaner a couple short sprays and see of you can see any carb cleaner spraying into the venturi, if not the port is plugged, repeat in the other side.

I have had the crap fuel we get today gum up and clog idle fuel the ports after just sitting for a while, i can usually just give the ports a shot of cleaner and clear them out.

I agree you could have a vacuum leak but i think you are compensating for the lack of fuel thru the idle circuts by screwing the idle screw on the linkage in too much thus opening the throttle plates too much and pulling the mix from the off idle circut.

[Redline novdog]

Sounds to me like one side of the idle circuit is blocked. Could be as simple as one of the new gaskets didn't get a hole punched correctly,or sludged up from sitting.The best way to clean a carb is in the agitator bucket of carb cleaner, and I have seen crap still stuck in the small passages.
Yes you can replace the tubes,these don't just fall out,or drop in. so if you go that route make sure you have adequate tools.
Unless your wanting the experience and fun of working on a Quadrajet,at this point I wold buy a rebuilt one.

[Redline novdog]

Forgot ( its to early) You can also purchase throttle shaft bushing kits to do away with the play in the throttle plate and shaft

[Redline novdog]

SCORE!!!!! Good job! And thanks for the update!