[Oldsguy]

I'm sorry I missed your last few posts. I have been checking here on a regular basis, just missed them I guess. I'm not sure how to solve your problem but I do know that you need to replace your thermostat. Your car will take forever to warm up in the winter without it and that just throws the choke circuit off too. You need to fix that. I still think a vaccum gauge might help you find your problem. get one and put it in a vaccum orifice on the manifold, you should have a good 15 to 18 inches of vacccum easy when the engine is warm, then, when you goose the throttle it should drop to about 5 inches temporarily. If you don't have that, you know you have a vaccum leak someplace. You said a few posts back that it ran better when you plugged off the booster. Do you mean the place on the back of the carb? It is larger size that most vaccum lines. If so, that is the right one. Try that again, let the engine warm up all the way, then drive down the street a ways and back, don't go too fast and stay in a residential area, you should be able to stop the car without the booster it would just be harder, unless you are really small or have weak legs it should work. don't step on it just tool around real easy like, if the car runs fine that way you have an indication that the booster may be leaking. I don't know what car would be a good donor for one. After you get that problem fixed and you can drive around easy with the new booster (if you needed one) then try driving harder and opening the secondaries (you DO have a quadrjet, right?). If you still have a problem it may be in your timing or secondary circuit.

Thermostat first
Vaccum leak second
carb/timing problem third

Good luck.