1990 4runner runs like crap when warm (V6 3VZ-E Auto)
 

Hello to all and thanks in advance for any and all help.

I have seen many people have this problem and the solutions have been varied. For that reason I want to ask you guys cuz im running low on funds and cant go around replacing a ton of parts. I figure if i ask you guys my specific problem i may have a better chance of fixing it without wasting too much cash. So lets start!
It's a 1990 v6 4Runner with an auto tranny. The problem is a weird idle that sometimes leads to stall, in regards to power when she's cold, she has plenty of power, the moment the temp gauge gets to around 1/4 of the way to hot I lose power from 2000 to 3000 Rpm. If i floor it, i get nothing for a while then a sudden surge of LOUD POWER.

Its throwing 3 codes;

• 21- Which is o2 sensor (have not changed, was going to wait for some recs since my money is limited and hope that my next expense is the one that hits the nail in the head)
• 51 -switch signal park neutral position, not in P or neutral (no idea though it might have something to do with the fact that i can move the shifter without pressing the break so something is def not right there)
• 52 - knock sensor

I have changed;

• Throttle Body with TPS
• Changed the MAF
• Cleaned the Injectors
• Changed fuel pump.

All these changes have made the loss of power less crippling but its still there. Its so sad because its so nice when warm then it goes DERP and puts me into a depression.

Additional information for diagnostic purposes;

• I have not changed the Temp sensor but i have recently read that might be the culprit
• it smells like its running rich, the car reeks of gas, especially after it warms up.​​​​​​​
• gas mileage is atrocious (moar atrocious)

Thank you in advance for any and all help

A knock sensor code will put the ECU into limp mode, it is typically a cheap to fix wiring issue (unless you drove into a lake or pulled the sensor and smashed it with a hammer), a very common location for a proper rats nest if you live anywhere there are small rodents. I would start with that, it is pretty important. It will cost maybe five bucks for wire, another five for fipg and time.

I'm with Co_94_PU. Code 52 may not be your ONLY problem, but it will make the truck run like crap, by drastically retarding timing. (and it's not the warm-up; it has to reach a certain rpm to actually throw the code).

The MOST likely cause is a failed "pigtail" . The bad news is that the intake manifold has to come off to get to it. But you have to do it. I wouldn't try soldering on a piece of wire, or "relocating" the sensor, or other "alternative" fixes. That way lies madness.

Update!

OK so im taking the advice and ordered the pigtail and to be safe the sensor itself, but i had already ordered a denso oxygen filter and i'm happy to say the power loss when warm is gone after the sensor. It still feels Underpowered but as you guys said, im sure thats code 52. Anything else worth replacing since i gotta open the engine so I can save time and money and do it in one blow?

P.S. Also im pretty sure the gas smell is a leak, going to investigate)

Thanx again for all the help.