1997 Running Rough, figured it out???

[klingon20]

I just recently purchased a 1997 Ranger with a 2.3 eng and auto tranny.

I did a complete tune up once i got it home to include the PCV valve, the continuing problem has been when you start the engine up cold it runs good but once it starts to warm up it runs rough and has lots of engine vibration.
I bought MAF sensor cleaner and sprayed down the MAF, I have also eliminated the AIC.
I have a ODBll reader and there are no codes, so the fact that it starts to run rough 20-30 seconds after being started and i dont feel the pressure coming from the exhaust i think should be there, it leaves me with the only logical conclusion, the catalytic converter is bad.
I will disconect the cat from the exhaust manifold to confirm this, but Im not sure i realy need to.

 

[blisted]

If you have a O2 sensor on the engine side of the cat try taking it out to let exhaust vent out. May be easier than disconnecting the cat initially.