Hello YotaTech, I am in a bad spot right now. I have a '97 taco w/ a 3.4L v6 with a TRD supercharger (added aftermarket) and I am experiencing misfires on all of my cylinders and I cannot figure out what is causing it.

I just got my engine put back together after replacing the knock sensors and wiring harness. While I had it apart I replaced the intake, plenum, and throttle body gaskets, spark plugs and plug wires. Cleaned all the surfaces. I followed instruction that I found through different forums and youtube to take it apart and put everything back together torqueing everything to spec.

When I started it up I could automatically hear/feal that the engine was misfiring and after a couple minutes it threw these codes as well as had each code a second time but Pending:

P0300 (misfiring cylinder problem)
P0301 (cylinder 1)
P0302 (cylinder 2)
P0303 (cylinder 3)
P0304 (cylinder 4)
P0305 (cylinder 5)
P0306 (cylinder 6)

I checked that all the hoses were connected and didn't notice any signs of leaks, all plug wires are in the right order, I even put the old plugs and wires back on it with no change.

What should I do and where should I start?

 

Quick update on what is going on here. I have been working through it and found that my bank 1 O2 sensor was bad as well as cylinder 1 injector, replaced both. I cleaned the MAF. Still did not help stop the misfiring and the same codes keep coming back.

I have replaced multiple vacuum hoses that were somewhat weather checked and went back in and used gasket sealer to make sure there were no leaks coming from the intake or plenum gaskets.

I bought an updated scanner to read live data and am seeing that at idle my short term fuel trim is running high, between 10 - -0.8% and my MAF is reading slightly high.

I have seen some posting where checking the crank position sensor could be an issue? Been sitting at the mechanic for 4 hours and they still cannot figure out the issue. Could I have gotten bad knock sensors that is causing this? I would think that would throw the knock sensor code again, and I checked the ohm and got nothing, which is what the FSM says you should get.

 

Did you find a resolution to this?

 

Update: Took my truck to the mechanic and it turned out that my timing had jumped about 3 teeth and my camshafts were advanced. That has seemed to fix the issue at hand and the truck runs well. My fuel trims are still a little off and MAF is slightly high at idle.

I am now dealing with a P0172 - Rich bank one and after re-fueling it is very bad and my truck doesn't want to accelerate or drive. Almost stranded me on the side of the road but luckily after a bit I was able to get it going and drive it. While driving it will randomly rich out a bit and get sluggish for a second, until I accelerate.

Some stats from when the code was thrown going about 60 at 2000-24000 rpm:
STFT B1: -10.9 & 0.8
LTFT B1 -30.5 & -30.5

 

Update: Took my truck to the mechanic and it turned out that my timing had jumped about 3 teeth and my camshafts were advanced. That has seemed to fix the issue at hand and the truck runs well. My fuel trims are still a little off and MAF is slightly high at idle.

I am now dealing with a P0172 - Rich bank one and after re-fueling it is very bad and my truck doesn't want to accelerate or drive. Almost stranded me on the side of the road but luckily after a bit I was able to get it going and drive it. While driving it will randomly rich out a bit and get sluggish for a second.

Some stats from when the code was thrown going about 60 at 2000-24000 rpm:
STFT B1: -10.9 & 0.8
LTFT B1 -30.5 & -30.5