Transmission and engine are OK

my car recently had some loose front flex disc bolts and this provoked a horrible vibration. I had no choice but to drive it as it was for two days and I couldnt speed up over 40. This week I got a new front flex disc and replaced it but the VIBRATION DAMPER (rubber disc that goes parallel to front flex disc) is all shrewed and I decided to "eliminate" it. Now my driveshaft doesn't have that damn vibration damper disc. I don't see that disc availalbe at parts shop.

Besides that, I was recently playing with the adjustment of the idle speed and changed my fuel distributor as well as throttle body.

This week I realized that THE CAR DOESNT' GO OVER 50 OR 55 MPH and it hesitates a lot between shifts (it's an automatic). And if I want to reach 55 mph I have to press the gas pedal really hard, as if there is an incorrect setting somewhere.

A mechanic, though he says transmission and engine are OK, says something like a "catalyzer" or something like that is clogged.


Any ideas ??????????????? thanks .. This is very recent

incorrect driveshaft position maybe a quick adjustment ??