At 09:58 AM 7/1/2002 -0400, you wrote: >every once in awhile my '74 imp will start running somewhat rough; not bad >enough to stall,just idling rough..if a/c is on it becomes more >pronounced...after a brief period, it quits and the idle smoothes out and >it drives beautifully.....then it may start again,etc.... I have this problem on my 2 68's too. And they have different carbs (Carter and Rochester). I think its the idle circuit in the carburetor. It occasionally gets dirty, and does not provide proper mixture. I have learnt to live with it. A super high speed run with a sudden close of the throttle sometimes helps clean the idle circuit (as well as the plugs). The very high vacuum created by the closed throttle and high engine speed could suck the restrictions off the idle circuit (remember, fuel is fed at idle not from the venturis but from the idle circuit, fuel flow driven by manifold vacuum). D^2 D^2