97 f150 4.6L.
im losing all power when hitting passing gear. like, its not even reving up. it hits about 2500 rpm with the pedal to the floor and drops down to 1500 before its sounds like it wants to rev back up. today, when parked, i hit the gas after driving to work and the same thing happened with the 2500 rpm power loss. i am running straight pipe. no cats or mufflers, but these problems were happening before i changed my exhaust.
so far iv changed or checked.

1. fuel pump changed
2. fuel filter changed
3. plugs and wires changed
4. coil packs checked and have good spark.
5. tested MAF sensor and is working properly.
6. PCV valve changed and hose checked, havent found any vacuum leaks ( have not done a smoke test, will in morning)
7. FPR valve checked and no gas leak.
8. EGR tested and with vacuum engine stalls.
9. fuel pressure checked with the new pump and sits at about a 32PSI constant. pressure does not drop when hit gas.
10. checked and cleaned throttle body
11. upstream O2 sensors changed and working properly

 

Have you tried removing the air filter and see if there is any change?

 

I had just changed it this morning along with the seafoam treatment. As of tonight on my way into work. I don't have any more problems....yet. About 85-90% of my power back.

 

runs good as long as i dont punch the gas and does make it up to highway speeds. takes a minute to get there. still have no passing gear. revs up to 3500 rpm and speed stays constant with no acceleration.
im at a loss. it seems once i reset my pcm, everything worked well for a couple days. could my fuel pressure be too low. The guy that had this truck before me has everything rigged to hell.
does any one have any suggestions please.

 

What might help would be if you were able to get the data stream info so we could examine what is going on.
This will require a scan tool to get this info.