Hesitation and Rough Idle

I spent today chasing the same problem on the 2 door Cutlass Supreme.
I was really hoping it would only need a tune up. (Plugs,wires,cap and rotor.)
I get exactly as you describe.
Shakes and stalls at idle smooths out when I drive.

My old plugs didn't look like any of them had carbon build up.
And the tail pipe runs clean.
I know carbs fairly well and your right it could be carb and /or mixture.
And it could be poor vacuum.
But it could also be a leaky head gasket letting water into a piston chamber or even sticky valves.
I don't mind to take off the heads and have them rebuilt just for good measure but I'm selling the 2 door to concentrate on the wagon (priority)
I am short on time.

 

mg: The White Stuff! Brrrr! Torture. Subliminal shivers...

Your wagon looks great. Said it before, but it sure looks awesome.

 

That'll seal it up, if there is one, until you get it rebuilt. Just let it cure for 30 minutes. It's got silicone in it anyway, so it'll peel off when you do rebuild it.

 

If these cars have sat for any length of time with gas in the carbs, they will get vanish-like deposits. If you're not into rebuilding it you can try running a tank of fresh gas with some seafoam in it. I'm running into this problem with a boat motor right now and have tried this. The idle circuit has already smoothed out.

 

Yeah I did the seafoam thing already, Im sure its just a leak like many have said on here and by the test I performed
Thanks
Bernie

 

I just started having a similar issue with my car too. I have fuel injection. I have a feeling that it's being caused by the alternator. How likely is that? In my particular case, my alternator is only about 9 mo. old. But the car seems to have a history of going through alternators and batteries.