hi i finished swapping a 3.4 from a 01 4Runner with an auto trans into my 92 toyota pickup with manual trans not too long ago. it runs great and everything but once its warmed up you will be driving and once you floor it or it gets to higher rpms it just goes flat and stops pulling. it has also been getting very bad gas mileage. when the truck is cold though it doesnt do it anymore it keeps pulling all the way like it should until its warmed up again, then the power starts going flat again when you floor it. has anyone ever had a problem like this before or have any idea what it can be?

 

Are you able to pull any engine codes? If it runs ok while cold and gets worse once it warms up that makes me think it your Air Fuel Ratio isnt correct after the engine goes into closed loop. Have you tried checking your o2 sensors?

 

dont have any diagnostic tools so cant see any codes, ill try checking out the o2 sensors.

 

What ECU? Did you trick the A/T ECU to think it's in neutral or did you (do it right and) use a M/T ECU from a 2000 4Runner (I think that was the last year of M/T 4Runners) or a 2001 Tacoma?

 

so i went ahead and bought a code reader and noticed P0325, P1130, and P0171 codes come up. Ive seen p1130 is the o2 sensor but i have just replaced the front one, and i saw in another thread the MAF can pop up that code but i had just cleaned that off recently with electric cleaner. so my question is can the rear o2 sensor set off that code too? i have not replaced that one. also P0325 is knock sensor can this affect anything at all as well? *edit* well after googling what a knock sensor does it sounds like that could be the problem.