1993 Mercury Tracer I never got a responce back from you si

Engine Performance problem
1993 Mercury Tracer 4 cyl Front Wheel Drive Automatic

Is it possible to get a responce if you dont donate?My Question was sent on 6-7-08 and still has no responce.

When I start car it will Idle up to around 2500 rpm then down to 400 or 500 rpm then up again to 2000 rpm or 2500 rpm and it keeps doing that for about 5 minutes then it goes to almost a stall or about 100 rpm or to a stall.
I have replaced the spark plugs and fuel filter, but when I tried replacing the pcv valve it starts then Immediately stalls so I kept the old pcv valve on, I have cleaned with spray carb cleaner the inside of the intake carb after removing the air intake hose that goes down to the air filter well I guess its called the carb it is fuel injected. I even put 3 bottles of heat in the gas tank because there seemed to be excessive moisture coming out of the tail pipe and through a small pin hole in the pipe going to the tail pipe and muffler area that is about in the center of the car on the bottom but that pin hole has been there for a few months now. What do you recommend I do?