3.4L w/ ETCS TB cleaning

I just finished. It was pretty gunked up in there but honestly I expected a lot worse. Throttle response is much better and she idles like a brand new truck. Here are some before and after pics. Ordered a new MAF sensor just because the old one does look like it needs replacing.

 

If you can cancel your MAF order, do it. If your MAF goes bad, you'll know it and be throwing a CEL code and your engine won't run right. At the very least, don't throw your old MAF away because it's perfectly good.

 

@QMEDJoe That dark bulb on the side of the MAF tube is the intake air temp sensor, the actual MAF sensor is way up inside the tube. Looks like a pair of little resistors, very delicate. Don't touch, just spray, no matter how tempting.

If you are aware of this then carry on.

 

No shiz? I didn't know that. I'm happy to know that now though? I mean yeah, I think we knew there were additional sensors besides that amber looking bulb thing, but didn't which was which.

 

Later year v6 small type two screw MAF.

 

The side that the air passes is kind of looks a little corroded and worn. I think it was like $50 on Amazon. I think that’s what I’m going to do is box the old one. I’m hoping to go full time overlanding by next year and that will be one less thing I need to worry about.

 

Thanks, I knew about the ones inside the tube and not to touch them but didn’t know which was which. Thanks!

 

Hey guys quick question for you here that I hope you can help out with. When I turn the throttle lever it doesn't engage to turn the butterfly until about a 20-degree turn and then it never opens up all the way up. Is that normal? When I take the TPS off I can turn the butterfly instantly with the lever from that side. Would that mean that the accelerator pedal position sensor is probably bad?

 

that's how it's supposed to work

it's referred to as "limp mode" so in case your APPS or TPS fails you can at least get a little throttle to drive slowly

the butterfly is operated by the motor "beneath" the TB (used to be the IAC) and is controlled by the ECU now, hence the "drive-by-wire" moniker

I was confused at first when I started looking into things but learned Toyota switched the 4Runner in late '00 and the Tacoma in early '03 to this style. All later Tacomas are electronic TB and no longer cable-driven

 

I was wondering if anyone might have an experience with this. 2003 4X4 tacoma V6 4 pin Throttle position sensor. I had gotten the code p2121, replaced the sensor and it worked ok for a few days. Now it's back in limp mode. I tried adjusting the sensor. Sometimes the code will be p2121, p2138 and p2127. I was able to adjust the sensor, cleared the check engine light and it worked fine again for 2 days, now it has a p2121 and limp mode again. It's a brand new Aisan sensor I replaced. Does anyone think it could be the APPS in the front of the throttle body? I know those can't be replaced and have to get the entire throttle body.

 

the p2121 references the pedal position sensor, aka Accelerator Pedal Position Sensor (APPS) so you may have already diagnosed the issue.

I have not seen the APPS separately but if you can find a used 03-04 Tacoma, 01-02 4Runner TB you may get lucky. I surmise the APPS has a low failure rate as I have barely seen any posts about it.

 

Headed out to my local salvage yard to get a used throttle body for my 04. I’m sourcing it from a 01 runner thanks to this thread. I tried replacing the TPS but am still getting an error code for the APPS.. I was hoping the replacement TPS would’ve fixed my drivability issue.

 

Wow! What great information. That is exactly like mine. I had no idea that the TB had coolant lines running to it. I gave up on removing the four screws on the top for fear of stripping them. Now I am certainly going to try again.
Could you define "IAC" and "ETCS"?

You So Much!
FTG (Florida Taco Guy)

 

IAC = Idle Air Control (valve) that the 95-02 had below the throttle body itself. When Toyota moved to the ETCS-i (Electronic Throttle Control System with intelligence (i) ) the IAC part got removed and the computer now controls the idle and butterfly in the throttle body with the motor that is below the TB