1997 Land Cruiser multiple misfires. P0300, P0305 and P0306. (1 Viewer)

[LoneWolfX611]

My toyota 97 land cruiser is having multiple misfires and i dont know whats causing the problem. Please I need help! P0300, P0305 and P0306.

Ignition coil replaced
Crank shaft position sensor replaced
All spark plug are new
All spark plug wires are new

 

[Maleficio]

Distributor.

 

[mct75]

Wiring harness by EGR and glove box perhaps too.

 

[landtank]

Does it run like there is all those misfires, or run smooth

 

[LoneWolfX611]

Thank you all for your quick responses. You guys are all awesome! So the engine will start running fine (not too rough) for about a minute or so then it will sound rough and shaky after that. I tried pulling the spark plug wires of cylinder 5 and 6 while engine is running and it did not have effect on the engine. I will try to upload video if i can. I still have to check if there's a good spark on spark plug wires number 5 and 6. Again thank you all. If spark is fine is it possible that fuel injectors on 5 and 6 went bad? would that even be possible at all? Can I upload video here?

 

[LoneWolfX611]

Possible to post pics of where those wires at? Thank you!

 

[LINUS]

Any chance you unplugged & replugged the fuel injectors in all this funtime?

Seems like we did this recently, the 030_ series codes were in that family IIRC.

From memory I can't say which, but fuel injectors are my 1st thought.

 

[landtank]

If you haven't done this you might try clearing the codes.

 

[theish]

How long as this been going on? Last two times I had major misfire problems it was due to bad gas (from shady gas stations) if this has only started happening since the last fill up maybe drain the tank and refill at a known good station. Sounds silly but can def be a problem if there is water or whatever in it.

 

[Maleficio]

How long as this been going on? Last two times I had major misfire problems it was due to bad gas (from shady gas stations) if this has only started happening since the last fill up maybe drain the tank and refill at a known good station. Sounds silly but can def be a problem if there is water or whatever in it.

Good point. I'd just pour in a couple bottles of Heet and see what happens.

 

[LINUS]

Did this start right after the plug/wire change, or more like after a fillup of gas? - if there was a decent time in between those 2 events.

Have you 2x checked you didn't mix up leads - it happens.

Without a better timeline I can only guess it's in the spark cycle or injectors, and that's a broad window.

 

[newtomelx]

X2 on checking the wiring harness that passes really close to the EGR valve! That was the same problem I was having on my '97 LX and it turned out a few of the wires had gotten "cooked" by the close proximity to the EGR valve over the last 19 years and had made the insulation on the wiring brittle, some had flaked off causing it to short! Check the wiring harness carefully! Re-tape the wires than you can wrap the harness with heat reflective tape to cut down on future issues there.

 

[Equinsu ocha]

You get this figured out? I’m in the same boat. Full tune up, new 5 and 6 injectors. Happened after I got gas, but I would think it would be more inconsistent with which cylinders it wants to pick on, not just 5 & 6. Codes have been cleared several times, and it keeps coming back. All wiring has been checked.

 

[L450X]

Reviving thread.

Any consistent remedies found for the misfires on 5 and 6?

If anyones had great success with finding bad wire shielding on the harness by EGR, any pics of the wires messed up for reference?

I’ve gone through all that most have plugs, wires, disy, injectors and pressure reg. Also drained bottom gallon of fuel from tank after it had sat a week then added heat.

So far none of that solved the misfire so assuming we’re looking at wires next.

Just looking for any success stories and possibly pics of problem wires if anyone has some.

Thanks for any help y’all can provide.

 

[Equinsu ocha]

Reviving thread.

Any consistent remedies found for the misfires on 5 and 6?

If anyones had great success with finding bad wire shielding on the harness by EGR, any pics of the wires messed up for reference?

I’ve gone through all that most have plugs, wires, disy, injectors and pressure reg. Also drained bottom gallon of fuel from tank after it had sat a week then added heat.

So far none of that solved the misfire so assuming we’re looking at wires next.

Just looking for any success stories and possibly pics of problem wires if anyone has some.

Thanks for any help y’all can provide.

Ended up being a blown head gasket. Run a compression test.

 

[L450X]

Bummage, that was my fear but was trying to avoid looking that way.

Thanks for the quick response, I’ll give it a test.

 

[L450X]

Ended up being a blown head gasket. Run a compression test.

Welp, you were right, blown head gasket.
Thank you for the tip

 

[Equinsu ocha]

Sucks man but I’m glad you know what it is.