i have a 2000 monte carlo ss with 201k miles and 75k on the second transmission my question is that it seems like its missing but its not missing it seems like its poping out of over drive like a stutter or missing feeling while acceleration but once up to speed, and not shifting it goes away then it happends once in a while while shifting, any ideas? pretty sure its trans not engine, i replaced upper intake gaskets, spark plugs wires etc. that didnt do anything. might need a tranny service? i am over the 35k mark also.

 

Sounds like you probably have a bad solenoid or two in the tranny

You could change the fluid & filter, but your TCC solenoid and/or PCS could be failing...

 

Could even be a clogging cat.