Just last week I just got a check engine light pop-up and suddenly the truck will not go any faster but can still giong about 5 mph, when I got home it popup a code 52 as knock sensor or circuit but when I check the TPS it seem to be acting funny as you can easily spotted the problem is on the TPS were the sensor keep moving when you give gas into it so does it really the knock sensor or the TPS? is the TPS causing it to think it is the knock sensor? I will be heading to the dealer tomorrow for the TPS so how much will the TPS will cost me? I kind of low on the $$$...

1992 TOYOTA 4RUNNER V6

Commonly the braided co-axial like knock sensor wire leading to the ECU (EFI computer) becomes defective (rusted/corroded) at the ECU located in the front passenger kick panel.

Sidney® ™
Repairs tv's,vcr's,home/car audio out of my home
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1985 Toyota 4-Runner,solid front straight axle,factory cruise control,sunroof,22R-E,W56,RN60LV-MSEK,rusted rear step/towing chrome bumper with 247 000 KM

Have you done ANY work around or near the throttle body and the main “engine wire” harness that runs directly behind it?
There is a pigtail that runs from the harness connector down to the knock sensor it is a VERY COMMON problem as the insulation on this pigtail becomes brittle with age and heat then cracks then the wire brakes. When ever an intake is removed on these engines it is common practice to replace this with a new one. Just moving the harness topside cna cause the wire to break.

The knock sensor is a $150 item but rarely goes bad.

When the knock sensor signal is “bad” the ECU defaults to a retarded timing set point but this will only be noticed at fuel economy and a bit off the top end. It will NOT result in 5mph top speed!!.

TPS is expensive, but you can test and set up your own, very easily:

This is from the sticky post brian has posted at the top of this forum:
http://personal.utulsa.edu/~nathan-buchanan/93fsm/engine/93throttle.pdf

1993 Factory Service Manual for Pick-ups and 4Runners:
http://personal.utulsa.edu/~nathan-buchanan/93fsm/

Thanks for the reply, I have just open up the air chamber today and have the knock sensor check and it seem to be fine and the wire is still on it, it is still throwing me the code 52 which will won't let me go any faster than 5 MPH, the knock sensor is located inside the air intake manifold which I have to open up the intake in order to remove it but I don't have the tools for it to remove so I might just take it to the shop but should I send it to TOYOTA dealer or other? I heard TOYOTA charge you more or expensive. Also when I turn off the truck the key will get stuck but when I pulled the wire from the battery and then it finally unlock the key I don't know why it does that, all this started when I was taking out my stock deck and was giong to replace a newer deck, when I was taking out the old deck I can smell wire burning so I may think it maybe a wire burn some where inside the dash cause everytime I turn on the light the radio light will turn off and when I turn the light off the radio light came back on so it should be a bad circuit or wire burnt. Thanks again, 4RUNNER_RIDER..

You probably have two problems. Like what 4Wheel said, normally a bad knock sensor signal won't keep your truck from driving fairly normally. You will get bad mileage, but it should accelerate. Replace the knock sensor signal wire. They are easily damaged internally. Then figure out your next problem.

I can smell wire burning so I may think it maybe a wire burn some where inside the dash

Did I miss the part about a burned wire???? This is most likely your source of a lot or ALL you electrical issues, especially the ones that "STARTED" just after the burned wire happened.
When a wire burns it melts the insulation and the insulation of EVERY wire it crosses or touches. Since it is most likely in a wire harness that could short a lot of wires even causing an erroneous error 52.

You will want to verify if there is a burned wire anywhere as ANY shop will have to do the same thing and it is not any easier for them than you, except they will get to charge you by the hour.

This can be a mess and very large job, as the harness may need to be replaced.