Alright, I would start with fuel injectors and spark plugs.

O2s should be good because if they were bad, you would get a system rich code. When a O2 sensor gets old, it cant get the proper reading and richens the system up.

I say fuel injectors because as they get old, they become plugged. The system can compensate for this a little by upping the flow through them, but eventually they cannot produce enough fuel and they lean out the system.

I would also replace the spark plugs because if they were running lean, the electrodes might be fried.

I wouldnt mess around with the cat just yet, as you may just waste money on them if they arent the problem.

 

Alright. Thanks for the suggestion. i will try those two things this weekend and drive it around a while to see if there is improvement.

Thanks again!

 

also replace the distributor car while you're at the wires and plugs. I wouldn't think the injectors are bad but anything is possible. Also you could be looking at a burnt valve. But start with the cheaper stuff first.

 

Your problem could also be caused by a faulty IAT sensor in the intake manifold. If the sensor is faulty, it'll read excessivly cold incoming air temperatures and cause the PCM to dump more fuel into the the fuel system. Cheap to replace and only takes a few minutes to do.

There's no plug wires or dist cap on a 4.7.

 

oops missed that he had a 4.7