1997 Chevrolet Monte Carlo Z34 3.4l DOHC, transmission shifts smoothly but looses power and speed. Appears to have plenty of power in first gear only. Problem is getting more intense every time it gets driven. Seems to get worse as the engine temperature increases/warms up. 4k on new motor and 108k on transmission. any idea of what this could be?

 

bad catalytic converter?

 

Haven't completely ruled out the cat, but the performance in first gear tells me that the exhaust is not plugged.

 

all our cats in all our gens seem to go bad very quickly around 100-150k on the odomiter some get more miles on it till it gives but i would def say it is the cat

 

okay, thanks. that will be the next thing on my list to do.

 

whens the last time you changed your 02 sensor? bank 1 not bank 2.. crazy i live in grand blanc too small world

 

I have changed the o2 sensor and still the same problems.