OddyseusDSM

ok, i feel pretty comfortable with cars but this is just puzzling. my car has a pretty good feel in the low end but the power seems to drop off kinda. some days it'll work like a dream for a little bit, it'll just run perfect. sometimes it feels like the clutch is slipping or something. no doubt the clutch is probly not grabbing completely but it wont rev and not accelerate at all, it'll also lose power between 2-3K rpms OR 3-4K rpms (thats as its warming up at a slow acceleration). but anyway...

when i accelerate i can never floor it, on a good day i can get it to about 75-80% throttle and itll accelerate, but if i go any more it'll feel like the engine is under heavy load like i'm drivin' up a hill. also if i floor it (100%) and bring it back a little the car will buck slightly and then start accelerating a bit. now, i've replaced the fuel filter, O2 sensor (car was running hella rich and i think the problem started occuring then), air filter, and removed the tube to the airbox. it felt better after each thing was replaced but it doesnt feel like when i first got it. all oil changes were done on time, spark plugs have been changed twice, wires done. i wonder if the fuel pump is going, or the distributer is going, or is it a matter of resetting the ECU. any other ideas are welcome (i tend to overlook things) i just cant figure it out.