engine problems ka24de

[snowdrifts13]

i searched but couldnt find anything like what i got. one day i was driving and my car(91 240sx ka24de) just started having problems getting my RPMs up and i have no power. my engine stock so its not fast but i have about half the power i used to. it runs great when i start it up in the moring and its cold but when it warns up i lose power again. the only thing iv done recently is put a cold air intake on, other then that my engine is completly stock. i dont get a check engine light or anything. i took it to a shop and they looked at it hooked it up to this little computer thing i cant remember the name of it some snap on tool, and it didnt throw any codes or nothing. nobody i talk to can figure it out its weird. i dont feel it missing or anything either it does make a vary light noise almost like a bad water pump bearing not that i think thats what it is thats just what it sounds like and the sound comes from under the valve cover. any help will be vary helpfull thanks

[snowdrifts13]

also when the computer was hooked up to it it read my mafs as being totally fine. and my o2 senser was fine also. i read the about the guy right below me who is having power problems after 3500 rpms and what my car is doing sounds pretty similar

[240FeVeR]

Test your coolant temperature sensor.