2000 Toyota Tacoma (Very fast idle and no power)

Hello, I really could use some help. It is a 2000 Toyota Tacoma 3.4 V that has an excessively high idle around anywhere from 1500-2000 rpm's. When it first starts up in "open loop" in idles somewhat normal around 800-900 rpm's, but once you hit the gas there is a major lack of power. Once it goes in "closed loop" the idle continues to increase all the way up to 2000 rpm's. It will throw a P0171 bank 1 lean fuel trim code, but the fuel trims seem to somewhat normal around +/- 7%. Fuel pressure before the fuel pressure regulator is good at 44 PSI. When I do the WOT (wide open throttle test) the O2 sensor B1S1 reads .05vdc (very lean); otherwise the O2 sensor cross counts seem pretty normal. There is no obvious vacuum leaks that I can tell. Also, there are no individual misfires either. I verified timing with my oscilloscope and all seems to be good. I can snap the throttle and put it to the floor and there is no power what so ever. Any help is greatly appreciated.

Thank you in advance.
Brian

Sounds like a lean condition, you said the o2 reads .5v on snap throttle. Maybe suspect o2 ,but if 02 is working properly then suspect injectors

you need to look at both STFT and LTFT on banks 1&2. To have a P0171 the LTFT on bank1 is at +25. Bank 2 is probably close behind. sounds like you have a big vacuum leak, the trims will tell. with b1s1 at .05v you may have a 02 problem and a vacuum leak.

02's do not control the fuel in open loop. once the 02 have heated up they go into close loop and the voltage drops then they start to oscillate 100-900mv. by default 02's go rich at WOT. if b1s1 02 is staying lean then its most likely bad.

let us know what you find with the trims

Thank you for the information. I actually found that the MAF was extremely dirty which was throwing off the grams per second readings. I also found a few small vacuum leaks. Everything is great now! Thanks again!

Brian