Ok, like the title states, I'm referring to my 88 4Runner SR5 22re 5 speed.

For a while now Ive had a problem with the truck accelerating. its alright at idle, and at full throttle. Almost any RPM or throttle input in between, the truck just bogs and doesnt really accelerate at all like the timing is off. Its dead set at 5*with the ecu jumped. The idle dropped when I jumped it as well so its seeing idle and seems to be in bypass mode. Im also having a tough time keeping the temperature under control. When its acting its worst, the water temp wants to start climbing like a mountain goat.

After a few months of this, im starting to get a check engine light nearly every time I hit the highway. Code 52 (5 flashes, nothing for a few seconds, 2 flashes) Knock sensor fault. Does this mean the knock sensor is bad? Or is the knock sensor detecting knock and throwing a code? When the CEL comes on, it goes pig rich (according to the nose) and i hear popping through the intake upon accel. I turn the key off and crank the truck again, CEL gone and it runs like before.....

I just picked up a free pop up camper and need my truck to move it around, I cant be pulling a camper like this! any help would be greatly appreciated!

PS - Thank you Rad4Runner (Yota-Yoda) again for help with the starting issue. Such an easy fix, and Ive never had a starting problem since!

 

Sure its not code 25-- lean conditions?

This lean condition could account for the popping back thru the intake and running hot.

How long since a valve adjustment?

Check for vacuum leaks.

How old is your 02 sensor?

 

I myself have never replaced the O2 sensor, or adjusted the valves. Vacuum leaks I can keep searching for. Ive replaced about 75% of the hoses, but the rest can be replaced easily. How easily do the VSV's go bad?

 

Actually Ill go re-check the code, you got me 2nd guessing it now! I need to go drive it to make the light come back on.

 

The purpose of the knock sensor is to allow the ECU to advance the timing until it just starts knocking, then back it off. Code 52 means the ECU can no longer "hear from" the knock sensor. Is it knocking or not? The ECU can't tell, so it could have the timing a bit too far advanced, which could blow a hole in a piston. So to save your engine, the ECU dramatically retards the timing. Which means: runs like crap. Your symptoms.

The knock sensor itself is very tough, and probably isn't the problem. But the "pigtail" wire from the sensor to the harness is in a hellish environment, and frequently fails around, oh, 16 years. So that's my first guess.

The good news is that the part is only about $12 from the dealer. The bad news is that you have to take a lot of stuff off to get to it. But if you have code 52 (yeah, check it carefully), it's never going to get better unless you just fix the wiring. (Some people on this forum may suggest you install a second knock sensor hanging off the lifting eye, with the hope that can detect anything. Personally, I can't believe that would do anything, but it's your truck.)

 

This is why i love this site. Thanks gents! Ill report back the findings!