whats wrong now?!?!?

Ok today i changed my 1-2 shift solenoid and 2-3 shift solenoid and also the 3-2 Control shift solenoid is new. New filter ect......... The reason i did this is i thought one of them was bad because when i drive 1st gear is perfectly fine, same with second gear.......... but when the point comes where the tranny should shift to third it DOWNSHIFTS back to first! Does anyone have a CLUE what could be worng!?!? Im stumped!

I checked on all data and it said inspect the Pressure switch assembly (pressure manifold) for erratic down shifting..... Does this sound like my problem??

Thanks,
Steve

Man I don't know if it will help but I thought I would throw it at you anyway because it about drove me crazy before I finally took it to a buddy of mine that been doing transmissions for about 30 years to figure out and I never would have thought that would have been the problem. I had a '01 Malibu 3.8 would not change out of first into second until you let completely off the gas then it would change gear. I though it was the sensor took it to him he hooked it up on his scanner no codes he took it to the Chevy dealer it was a plugged catalytic converter. It was building up to much back pressure so I got out of trans work and just had to slap on a CAT now she runs and shifts like a dream.

I don't have a cat though.... I kinda wish that was the problem lol so i didn't have to worry about the tranny anymore.

I just took it out and drove it and like i said it shifts fine from 1st to 2nd but when i thought it down shifted i gave it some gas and there was nothing. it just reved??? anyone know?