95 buick regal running rough Please help

My car was leaking anitfreeze into the oil. so we changed the intake gaskets and that took care of that problem. But now the car is running really rough. there is a strong odor of gas. It also seems to be using alot of gas. When you stop a stop sign or go at a slower rate of speed it misses and acts like it wants to stall out. If you go 55 or higher it runs better but you can still feel its nots running correctly. We changed the o2 sensor but it did not help. Any Ideas? I am at a loss at this point!!

You don't say which engine you have in your car, but here are some things to check. Did you change the oil and coolant in the engine? If they were mixed with the problem, they need to be changed now. Also, pull, check, and clean the spark plugs; be sure the plugs and plug wires are in good shape. The strong gas smell indicates that all the cylinders are not firing and unburned gasoline is being expelled through the tailpipe.

Hope this helps, and good luck!

Yep, sounds like spark plugs to me.

Is there a possibility that when The intake got put back on it was over torqued or that a wire got pinched somewere? It does sound a little bit like spark plugs, but im assumign that it is a 3.8.......... all 3.8 are known for there intake manifold........ But is your check engine light coming on?
Bill