each_mc19

I recently rebuilt my Quadrajet on my automatic 78 vette. When I rapidly accelerate from a stop, it lags before it shifts to second or starts jumping up and down between gears. It performs fine everywhere else, idles well, shifts from second to third fine, no problems when I get on it when it is already in second or third, if I slowly accelerate it has no problems anywhere. Any advice would be appreciated.

Mick 72

I have the same problem and even bought a jet performance stage 2 brand new and it still does the same thing. If I find out before you I'll let you know.

lars

Try adjusting your 2-1 kickdown cable on the carb: Pop the plastic adjustment tab up, put the carb at WOT, and then push the tab back down. Verify your tranny modulator hose is hooked up and undamaged.

Lars

RATT7

Thanks Lars, speaking of my 1978 GMC truck this is a problem that I have noticed to. I thought it may be the kick down cable to. I will give it a try tonight!

each_mc19

Thanks for the advice Lars, I messed around with that carb for hours looking at my pre-work pictures to make sure all the hoses were in the right place, replacing damaged ones, finally got it working and it runs smooth. I am a rookie when it comes to working on cars but I like to do the work myself, I have now successfully rebuilt my first q-jet, which is a miracle.

7T1vette

You could also be running the fuel bowl out (or low). Check your fuel filter to make certain it isn't clogged up. Also check float height to make sure it is correct.