Help needed! 94 grand prix engine lopes and hesitation at idle speed

[dw_bobby]

Hi Guys!

My 94 Grand prix started to hesitate at idle speed (while driving) every now and then. When it happens the tranny acts erratically also, shifting up and down trying to pick up power. Returns to normal by itself shortly. Also, around the time it started to happen the engine seemed to work at higher temp then usual. I changed the temperature sensor, rad cap and did a flush. Temperature reaching 110C and fans lower it, by the book, although overall higher then before. No coolant loss. Checked so far and seem ok: PCV, EGR, TPS, IAC, vacuum lines, intake manifold.

I'd really appreciate your thoughts.

[dw_bobby]

Missed some details: 3.1L engine, 180K miles, should have a 4T60? Sometimes the tranny won't shift beyond 3rd, mainly in the summer. Few minute stop and goes back shifting all the way. In the winter it happens very rarely. I thought it was a solenoid, but never gotten around to check it thoroughly.

[dw_bobby]

Finally solved it. It was the trans, the engine was fine. Did a complete overhaul and everything is fine.