I have been trying to figure out for a while now why my 95 Ram runs so rough some times. I have replaced the cap and rotor and added new bosch plugs and wires. Could the O2 sensor be causing the performance drop or is it something else?

 

O2 sensor and the cat. I would say. If you haven't changed them.. over 85k or so, its time.

 

Runs rough or Idles rough?????
please go into detail!!!!
are you useing oil??
Codes???

 

The truck idles fine. It runs really bad when the truck is cold. Even when it warms up is still seems sluggish. The truck has 113,000 miles. I have a new high flow cat, but I don't believe the O2 sensor or the fuel filter have been changed. Is it difficult to change out an O2 sensor?

 

Changing an O2 sensor is as easy as it gets
but I don't think that's your problem
near your t-stat is 2 sensors both are engine coolant sensors, one is for the guage, one is for the computer.
Check both connecters for good connections!!!
Do you have any codes???

 

My check engine light comes on maybe once a month, but very rarely. As far as codes I don't know anything about them. I will check those sensors out. You don't think it could be a bad fuel filter? The truck cruises good, but when you mash the gas it will sputter and surge and finally kick in.

 

sounds like you might have a dirty or bad injector, try running some injector cleaner through there and see if that helps?!

 

I have tried injector cleaners before, but they didn't seem to help. Really the truck acts up when it hasn't been warmed up yet. It will surge back and foth and finally some power will kick in. I read about the symptons of a bad O2 sensor and I think that could be my problem. I might try putting a new one and if that doesn't help I will take it to the shop.