2003 3.4L TPS 4-Prong

Did you check all your fluids for water intrusion. Diffs and all? So no water got inside cab?

 

None in the cab. Changed most of the fluids but haven't checked the diff, good call

 

Check it soon!

 

Ok, so after a few victories and failures, it appears to be fixed. Prepare for a long post, and I'd like to preface it by saying I AM NOT A MECHANIC! But I'm a problem solver. And all the stuff I've done was up for regular maintenance anyway, so I didn't mind spending some money to change a lot of it out.

So, since my last post, I've done some work. First, I got the whole used throttle body with sensors. I took the TPS off and slapped it on my truck. Little tip: angle you put the TPS on makes a HUGE difference. One way too far and the engine constantly revved itself up and down. Too far the other way and it just dies or goes into "limp" mode. So I found a good happy medium, hooked it up, and tested it out. No real change. Still stumbling, losing power, still throwing CEL. So, I decided to just throw the whole replacement throttle body on since I bought it anyway. That seemed to clean up the stumble and major power loss at low RPM. But I still had a hiccup and the CEL would blink when it was under load at high RPM, and the engine just didn't seem happy when I floored it. Decided to just buy a code reader already. Checked the code, P0303, misfire on cylinder 3. Well, if you remember, I replaced the plugs, so I figured it was one of 3 things:

Plug Wires
Injector Coil
Fuel Injector

I picked up some plug wires and an injector coil for the hell of it and headed home.

Threw some sea foam in my tank and used the spray as directed... no change. Tried the multimeter on the fuel injector and number 3 was sitting at 16.7, well within range. Tried the "screwdriver test" and it sounded fine.

Changed the plug wires. After a rookie mistake mixing up the wiring diagram, I eventually got it sorted out. Issue persisted.

So... now for the ignition coil. Didn't think it would be it, since I've been told by multiple sources that if that was the problem it should be misfiring on 2 cylinders, since the coils run 2 cylinders. So I swapped the 1 and 3 coil and cleared my codes. Sure enough, went around the loop (that includes a nice little hill where it always throws the misfire code), threw the code, got home, read it, and got the P0301!! Swapped in the new ignition coil and that damn beauty of a truck is running better than I can remember. Test drove her for a bit, including hammering on the gas up a hill, and I swear she was so happy to be running smoothly I about did a wheelie in that thing.

I definitely made some bone-headed rookie mistakes along the way, but I am a rookie after all and learned a lot from these forums, so thanks for all the good write-ups and input on here! Gotta drive up to a higher elevation on the island tomorrow so that will be a good test.

Next fix is the tailgate latch. The threaded sleeves were spinning free in the handle, and won't come loose even after spraying some PB blaster on them... time to get out the grinder.

 

Glad you got it fixed..
Being able to read and clear codes makes all the difference in the word. What kind did you buy?

 

I know this is old but how did this all work?

What did you do to the 4 prong airing harness to make it fit into the 3 prone throttle body?

The pedal is deferent and it had a pedal sensor cable that is supposed to hook up to the throttle body. It wouldn’t be connected to anything if you swapped it out for an older throttle body.

And what about the transmission kickdown cable? It’s all electronic on the 03-04 as well....

 

I have 2, 4 wire throttle body's w tps if anyone needs them.

 

PM sent.

 

I know this is an old thread but this Aisian TPS seems to be a 4 prong, please correct me if I'm wrong.

https://www.partsgeek.com/catalog/2003/toyota/tacoma/fuel_injection/throttle_position_sensor.html

 

Yep thats it W0133-2744128