2003 tacoma complete loss of power under normal conditions

hello, i have a 2003 tacoma 4x4. i've been having an issue with my truck where the power completely drops and full depression of the accelerator does nothing. my only defense is to shift gears or, let off accelerator and coast for a while and then repress the pedal down. it seems to happen more often when the ambient temperature is high, 80's and up. i've taken it in several times throughout the last 5 years with no sustained results. it does not happen under load or while accelerating. it is when the speed is steady or when first starting out. mechanics have changed the mass air sensor twice, spark plugs, air and fuel filters, yet it's still happening...especially now that it's getting warm towards the end of summer. in my search for answers online, the closest post that resembled my situation talked about replacing the throttle body potentiometer. is there anyone out there with experience with this type of problem that could help me diagnose so i don't blindly throw money towards another mechanics theory? thank you very much!!!!

 

Any codes? It may not be related, but my wife had the exact symptoms on a 2003 Jetta. Turned out to be the crankshaft position sensor.

 

not sure about codes, but no engine light warning or other indicators. thus the diagnostic mystery. thanks for the info.

 

Very interesting that it doesn't give you any codes. Maybe a fuel pump issue as well. Those are the only two things I can think of given the things you have already tried. Fuel pump and Crankshaft position sensor.

 

This may help. Interesting diagnostic approach

http://www.customtacos.com/forum/15...2365-toyota-cranks-no-start-food-thought.html

 

thank you.... well it's in the shop as of this morning, i've passed on the info. i really appreciate your input!

 

The 'throttle by wire' would be my guess. No experience here though ( i still have the old-fashioned cable).
However, that system did fail me on a rental car once, in Hawaii. Started, idled, but nothing happened when I stepped on the gas pedal. I idled it down to the rental place, and got another car.

You must have some kind of a pedal-position sensor and a computer-controlled throttle actuator. Those should be easily verified with a multi-meter.

Let us know what it turned out to be. Good luck.

 

well it has turned out to be the throttle body that has failed. it seems to be an issue with the 2003 and 2004 tacomas. thanks for all the help

 

Good to know. Thanks for the follow up OP.

 

The throttle body? Can you give more details of the failure? Shaft wallowed out where it sits, jamming butterfly? Other?

 

more details.... the gears in the throttle body are misaligned and grinding. the butterfly only opens a quarter of the way and then somehow opens full under certain conditions. it's grinding and making all kinds of noise. i have a feeling this is something that i have been dealing with since buying my truck. hoping that the erratic throttle i've experienced since purchase will go away. i'm not a mechanic, but many people have posted about this same issue with the 2003 and 04 tacomas.