Still not sure whats wrong?

[SpeedStyle]

Well this is what i do know,
My car runs good when i first start to drive it, but about ten minutes into driving, the car doesnt perform the same, ill try to accelerate and it will for a second but then the motor makes a lower tone and the car and rpms wont continue to climb the same.This happens in any gear at any rpm. Ive checked the imrc while warm in park and it always opens up? Im also religous about seafoamin and fuel system cleaners, so i dont think it would be a clogged cat, or injectors.Also im not sure if this has anything to do with the problem but sometimes ill nail it and it could be at 3000 rpms and the tranny wont downshift, it just slowly climbs in the same gear?Ive had trannys go out on me in the past(3 times, not on a cougar)and i always seem to know when it happens, that may be the case hear but i dont think it is. ANY AND ALL INFO IS GREATLY APPRECIATED!!

[B3NN3TT]

Sounds like classic IMRC failure to me.

Unplug the wire to your IMRC when it's cold, and see then if it exhibits the same behaviour as it does when it's warm.

[skater]

Me too. But if the IMRC really is okay, my next thought would be a clogged catalytic converter. But do what B3NN3TT said first.

[SingleShot]

My car was doing this once. If its not the cat or IMRC check the rod that opens the secondaries under the TB. I've broke the clip/bushing there and it did it.

[SpeedStyle]

Well you guys were right again,thanks!! I had been checking the imrc warm, and it always opened, but today it was 98 outside and the problem started immediatly so i pulled over jumped out and check the imrc and sure enough it didnt open, anyway thanks again!