I’m new to the forum. I’ve been a used car dealer in Texas for 30 years and have always been a Toyota guy. I recently bought a 1995 Toyota 4Runner v6 4wd with 131k miles as a personal project. Truck has been off the road for about 5 years as best I can tell. The truck starts right up and everything works. The problem I’m having is that the truck runs perfect at start up and for about 1/2 a mile down the road then bogs down, barely moves under its own power and sometimes dies. When this happens several lights on the dash flash. The only code is the infamous 52. Fuel filter, pump and tank are new. Spark plugs are OEM NGK and look like it’s running a little lean. My question is will the lack of a knock sensor signal cause it to run that bad? Anything else I should check?

 

Welcome to YotaTech.

Yes. That's what code 52 means; the ECM has set the timing very retarded in a desperate attempt to save the engine.

Replace the "pigtail." It's in a hellish environment and is often the cause of code 52. The knock sensor itself is very tough and unlikely to fail, but by the time you get to the pigtail you might just as well replace the sensor too.

 

Yeah I’m gonna tackle that this week but I’m curious if the knock sensor/harness is what is causing the issues. I understand that the timing is being retarded because of the lack of signal but I can’t believe it would make it fall on its face this way. Has anyone else experienced a code 52 that caused the vehicle to barely run under acceleration?

 

There could be other factors at play, but you need to fix the known issue first.
could also have a clogged catalytic converter, but that won't likely give you a code 52