When my rig is warm it runs ok, when it is cold it runs real poor. No power and acts as if it is not getting gas. BUT it also will act like this once and awhile when it is warm but not always at the same time.
I have changed the timimng belt, adjusted the vavles, tuneup, the only thing that realy helped was when i adjusted the throttle position sensor, but after a while it started acting up again. I get no codes when i pull them other than 12(normal according to Haynes).
I have checked the fuel pressure... Fine
Backpressure at the tail pipe..... Fine
If the motor had a compression problem the symtoms would not be so intermittant Right?
Anyway i would appresiate all suggestions on what to check next. BTW my rig is a 1992 Sidekick 1.6 16 vavle 4dr 4x4 all stock.Thanks for any help you can give.

any ideas??

for the ecm to notice a bad sensor and give you a trouble code, the sensor has to register a certain value like shorted or open.   Some sensors, when they start to go, dont break enough for the computer to see it as bad but still effect the performance of your car.  The o2 sensor might be telling your car that the gas is 30 rich, your car readjusts to 30 leaner and now the o2 sensor is giving you a perfect signal, meanwhile the car is running like crap because its too lean.  If it does it  when cold, I would start with the o2 sensor and the engine coolant temp (there might be two, one for the gauge and one for the ecm). This last one would be telling your computer the car is normal temp thus turning off the "chocke".  
Not a compression problem by the sounds of it

I would need firther symptopms to get a better diadnosys

What else do you need to know? I will give you all the information i have, and is there a way to test these two sensors? what you are saying makes sense i would love to check it out further.

Had a Monte Carlo with the same symptoms once and it was the catalytic converter. It had broken pieces floating around inside restricting flow.

back pressure at the muffler checked out fine, if the cat was clogged wouldn't the back pressure be outside recomended specs?

how do you do a back pressure check?  I never heard of it.  it's only two bolts and springs keeping your cat connected to the exhaust, try separating them and starting the truck just so you can double check if the cat is clogged.  If there is buildup of pressure in front of the cat, the gas will be forced through the clog and at the tailpipe you can still get pressure reading.  If you have a welder, you can drill a 3/4 inch hole before the cat and check that way too

for the ecm to notice a bad sensor and give you a trouble code, the sensor has to register a certain value like shorted or open.   Some sensors, when they start to go, dont break enough for the computer to see it as bad but still effect the performance of your car.  The o2 sensor might be telling your car that the gas is 30 rich, your car readjusts to 30 leaner and now the o2 sensor is giving you a perfect signal, meanwhile the car is running like crap because its too lean.  If it does it  when cold, I would start with the o2 sensor and the engine coolant temp (there might be two, one for the gauge and one for the ecm). This last one would be telling your computer the car is normal temp thus turning off the "chocke".  
Not a compression problem by the sounds of it

I had the same problem as you :-/, had the fuel injectors cleaned with the OTC Kit, and power I did'nt even know was there was restored .

ZukkinMad

what is the otc kit?

otc "over the counter" (can buy at local store and not have it professionally done)
Zig

what is the otc kit?

Its a brand name, you can find them at the below link
http://www.etoolcart.com/index.asp?PageAction=PRODSEARCH&txtSearch=fuel+injector+cleaner&Page=1

Ahhhh, I see, Owatonna Tool Co. They cheated
Zig

Thers another valve on mine, on the intake manifold unconnected to the ECU. I think it is designed to up the idle speed, opens when its hot, closes when its cold. Forget what its called.

changed the collant sensor nothing, readjusted the throttle position sensor and it is a little better but still not right, ordered one from hawkins hope to get it soon, will check cat this weekend, anything else i should try?