3.4 bogging

I have 3.4 4Runner with 110k mikes. I have a bogging issue I can’t seem to figure out.

Here’s what the car does.
Boggs down and shakes really bad and acts like it’s going to stall when I press on the gas lightly. If I slam full pedal it won’t do it.only when you lightly press the throttle. Power Doesn’t come until 2k-3k rpm anything under 2k rpm is like a dead pedal zone. The runner hasn’t thrown any codes or check engine light.

I’m prepping for a supercharger so I added a upgraded and bigger fuel pump the truck had this problem with the stock pump also
I put brand new injectors, new spark plugs, coil
Packs and spark plug wires also changed the fuel filter. Cleaned the throttle body and the maf sensor and it’s still the same. I wanted to upload a video on what it does but the forum won’t allow me to. As of now I don’t really know what else to look for. And I don’t want to be swapping any more parts That don’t fix the issue. If anyone knows what it might be or had this problem. Your help would be much appreciated.

 

You don’t have a check engine light or a code? Seems odd... sure your cel bulb is good?

Clean/check the throttle position sensor?

 

99% sure it’s your throttle position sensor.

 

There’s not really any way to clean the TPS. Just needs replaced.

 

I’m not an advocate for shotgunning parts. he said there’s no CEL, so it’s possible the return spring could be dirty/stuck or contacts dirty inside, a little electronics cleaner may get it working correct again.

At the very least, he should remove, inspect and test the TPS. If the resistance specs are out of tolerance, and it won’t clean up, then yes it would need replaced. However I would suspect that case would be throwing a TPS code of some sort.

 

Not a single code. The bulb works for sure.

 

https://www.tacomaworld.com/threads/help-diagnosing-intermittent-engine-stall.348791/
Here’s the thread I started a few years ago when I experienced this issue. It’s fairly common on these engines, but it took me a while to figure out it was the TPS causing my issue.

 

It took my truck a full 2 years of intermittent failure before it finally set a code...

 

I’m going to go try and clean and test it and see where it goes from there.

 

This is what the sensor looks like, the white part in the middle turns with the throttle, unless you plan on taking it apart somehow, there’s nothing really to clean.

 

Honestly I’m just going to change it and clean the entire throttle body along with it .Oem or aftermarket? For the sensor?

 

I got a factory one from my local dealer for like $70. They had it in stock and it took about 5 minutes to swap out.

 

Go oem. Just got one from Amazon for $50.

 

Do they need to be calibrated or anything after the install?

 

Nope, plug and play.

 

I have a Toyota brand TPS for sale if you are interested, new in box, PN 89452-22080. If this is the one you need, and you want to buy it, I will give you a good deal on it.

Before you throw money at it, check it with a multimeter to make sure that is the problem. Based on your description, I would almost bet money your TPS is bad. Another tell-tale sign is, the hesitation gets worse as the ambient temperature rises... My truck ran great in the winter, but was undriveable in the summer. Mine never gave a code or CEL.

 

If it's plug 'n play and there's nothing to adjust, how come the mounting holes are elongated?

 

I did take one apart apart after it began acting up. I had already installed a new one, but got curious to see if it could have been repaired. I made a thread showing the inside, but basically it's just a rheostat. Mine had some grease/dirt that was causing a bit of a short. I could have glued it back together and I believe it would have been fine.

If somebody is cash strapped or somewhere without a replacement part, it's worth opening it up. A little silicone could seal it back together.

https://www.tacomaworld.com/threads...-position-sensor-impact-and-disection.558808/

 

They’re not... at least on my truck and in the pic I posted they aren’t, your truck may be different?

 

Like @Wsidr1 said.
The ones with slots can/should be calibrated, I forget the years/applications. The ones with holes just bolt on. Even they can be tweeked a slight bit.
Enterprising folks have gotten them apart and cleaned the rheostat coils and wiper. Initial dielectric lube may brake down over time and the contact surfaces can oxidize.

Really bad ones can be detected with the average DVOM and even by watching the OBD throttle position values for smoothness of progression as the throttle travels thru it's range.
An old analog meter with a large scale can pick up more subtle irregularities.