bamayote

i've been fighting a 171 code for a couple of months, and i'm just about to take it to the mechanic.
lemme give you a very brief history to see if anyone has anyone else has any ideas...........by the way... thank you dr z and everyone else who have responded to my questions. you've all been wonderful to help!
here goes........99 tacoma 4x v6 120k miles on it. at 95k i got a p0171 dtc, system lean bank2. changed the upstream o2 sensor. 1wk later got the same code, same bank 2, everything and it's been down hill ever since..lol
i've checked for vacuum leaks, changed pcv, changed downstream 02 sensor, new plugs (thinking burnt passenger side plugs), had a "mac vac", checked voltage on both 02 sensors per haynes manual, checked voltage and cleaned MAF sensor.
And now, for the last month or so, it's been really cold natured with major hesitation while it's cold, and for a while after it warms up it looses power at 2k rpm. The engine doesnt rev or anything. It just looses power, like i've taken my foot off the gas.

I'm thinking it's time to have the injectors pulled and U/S cleaned, and i'm betting it's the passenger side injectors that are the problem.
Is there anything else i'm missing? i've pretty much read the haynes manual front to back. I may sound a little frustrated, but truth be known it's been a great learning experience!! I always knew that i'd always have toyota trucks from now on, but since my knowledge base has grown a little from this experience i'm very sure i'll always own a toyota truck!

thanx again everyone and i hope i havent been too longwinded.
brad
rogersville, al

bamayote

i changed the fuel filter as well
sorry i forgot!

Fink

I'm having that done Friday...did you notice a big difference in performance?

I'll let ya know what happens when I do it...

Fink

bamayote

i'm going out of town this week so i'll probably drop it off next week when i get back. in the mean time i'm gonna clean the throttle body and check the TPS.

cya
brad

Unhappy99

The cold nature, power loss and hesitation, along with the p0171 code, all indicate (at least, to me) your MAF/IAT isn't working properly. I know you said you cleaned it, did you get both the MAF hotwire and the IAT bulb?


Otherwise, perhaps someone near you can loan you a known good MAF/IAT module to test?

Also, check fuel pressure. It could be low.

bamayote

hmmm...........cant say i checked the hot wire.... but will definetly check it.
the fuel pressure checked out ok when i had the motor vac flush.

thanx for the reply unhappy!!
hope you get happy!
lol
brad