testing TPS

I'd like to troubleshoot my TPS. I have a multimeter and feeler gauges, but I can't make sense of any step of the below instructions. Has anyone written up a clearer step by step? I've looked for videos, and I don't see anything that applies to this one.

I'm also willing to buy a new TPS if testing it isn't feasible. I think I would have to adjust a new one too as I install it, as per step 4? How do I apply vacuum?

 

The vacuum is probably to pull the dash pot plunger in, let the throttle plate fully close. You can probably do the same by just removing it. Then insert the feeler garage and read resistance across terminals as specified. If you can access the TPS with the truck running at idle and have a scan gauge, you can have the mounting screws snugged and move the TPS a little and check scan gauge for position indicated till it’s adjusted properly. I am basing this off my 2.7l so am assuming your 3.4 is similar, may be wrong.

The volt meter test probably goes the extra step to determine if the rheostat winding is fully intact and not compromised, carboned over etc. The scan gauge may also show it malfunctioning. You may see the TPS reading on it jump around when it hits a bad spot as the gas pedal moves through the range. Mine showed up at idle like that. There are posts here about pressing the gas pedal 100 times to swipe clean the contact in the TPS. I’ve seen at least one post where a fella took his apart and cleaned it.

At least that’s the way I understand things about it. Good luck.

 

Thanks, I think I get the idea now. The feeler gauge was confusing me, but now I think I get that the different sized gauges actually hold the throttle into certain positions.

The OBD2 data struck me too as the obvious way to test the TPS. I wonder why Toyota says to do the wacky method with shims and resistance instead of checking the exact friggin data? It reads with just key-on, super easy. Maybe a good idea to do the resistance check too to be thorough, I guess.

So my throttle position is at 12.2% closed, 75.5% pedal to the floor. Those are above spec, so I think I'll try adjusting the TPS first.

I'm going to order some little JIS bits and a right angle screwdriver to get it loose. Tight space back there...

 

Still should be fine set that way. When and if you replace the TPS, you might go ahead and replace the screws with Allen heads if needed. Will probably need little washers too. I replaced mine after rounding mine out with Phillips.
https://www.tacomaworld.com/threads...ith-stainless-steel-socket-cap-screws.364604/

 

Well that was easy. I ended up getting the screws loose with what I had and adjusted it. The one trick was the scan tool value for throttle closed position drops a % point with the engine on versus key on. I went with the engine on value. I didn't bother with the resistance checks.

I'll report back if I notice any change. My numbers for fuel trim, air flow, mileage, and everything else I see are good, so I'm just tweaking it at this point.