Very weird problem, experts please chip in
 

Hey guys, 01 Eclipse GT with 107k miles, manual.

Here is the problem, it comes and goes as it wants to, when I am driving or stopped at idle, and I rev the car up a bit, no matter how high of RPMs, my car sounds like a wind up car, like the exhaust tone goes very low, my engine revs fine, but sounds like the clutch is slipping (that type of noise) but it cant be my clutch because IT DOES IT IN IDLE ALSO!!! Plus you cant smell burned clutch after it does that. When the car is in that state, it feels as if more than half of the power is lost, it is harder for the RPMs to build up, acceleration is worse, and just power overall is like on 1/3 instead of %100.

Then all of a sudden, it stops, and starts to act normal again, power will be restored, acceleration would be fine and it would run good again. Then then problem would come back when it pleases. Thats what makes it hard to narrow down, because it comes and goes WHENEVER!

Now, could this be cause by a bad EGR valve?

My upgrades / new things; Spark Plugs, wires/coils, rotor cap and dist, fuel pump, air filter, fuel filter, exhaust, air intake valves (12) new head gaskets, new head bolts, new stage 3 clutch, engine grounding kit, new timing belt, new water pump, new P/S pump and thats it for the engine, tons of cosmetic and interior (but thats irrelevant)

So guys, if you would have the slightest of knowledge on this problem, please enlighten me, as this problem is sooo annoying, and terrible for performance.

Thanks,
Lost

The car threw out a P0154 code yesterday, bank 2 sensor 1 o2 sensor not reading or something.

Causes: Faulty Connection, Lean / Rich A/F mix, Faulty o2 Sensor or fuel delivery problem.

I also had the timing done, now since this is an interference engine, what if one of my crank wheels is off by a tooth?

My car would still run fine, but it could cause a problem like I was describing.

Either way, going to mechanic today.

Ill let everyone know what it was.