'01 2.7L 4x4 ext cab. 125k A/T.

The truck has very sluggish acceleration at low RPMs. From a dead stop, I will slowly but steadily accelerate, even if I have the thing nearly floored (just above the kickdown switch) acceleration will not improve. The same slow steady climb. Its not stuttering, doesn't feel like any misfiring, its just a major lack of power. It feels like im towing a house uphill.

Now the odd part: As soon as I get right around 2500 RPM I suddenly have power and the truck takes off. Its a very sudden and dramatic boost, not a gradual increase. Ill have crap acceleration at 2400 RPM and then have excellent acceleration at 2500. It is not the tranny downshifting (that was my first thought), its just like something kicks in at 2500 RPM that makes the engine go. This happens 100% of the time when accelerating from a stop.

I've had the truck about 2 months, I have replaced the front O2 sensor, MAF, fuel pump, TPS. Have fresh synthetic fluids in all the gear boxes and tranny. Did a piston soak and put new spark plugs in. Ran some fuel system cleaners through the gas. PO told me the fuel filter had just been done. The air filter is some cheap chinese thing with a crappy gasket, I have a OEM one on order but I have my doubts that will solve the problem. I am really out of ideas.

 

transmission is full? did you try manual shifting it? i wonder if its not down shifting and its staying in second gear or something. how does the engine rev in neutral or park?

 

I recently did a trans flush and I was pretty careful with getting the correct fluid level in there. It revs fine in P or N, and the acceleration at speeds over 30mph is fine. Its just from 0-30 that theres a problem. I can get the tranny to downshift if I want it to, but it feels like its in the right gear theres just no power. I will get that "turbo boost" right around 2500rpm, and thats without switching gears. So the power is there, the truck just isn't using it from 0-30 for some reason.

 

Has it always done this since you got it, or did it suddenly start?

Sort of sounds like it could be cam timing off a tooth or so?

A strangulated would give you an opposite symptom - run just fine down low, but as the revs climb, it can't move enough air through.

 

Its done it since I got it about 2 months ago. Overall with the basic tune up stuff and fluid changes I've done the acceleration is better now then it was before, but still missing something.

I haven't checked the timing of it, would that normally throw a CEL?