Toyota Troubleshooting a Toyota 3.4L Cylinder misfire

[sixstringsteve]

It humbles me to admit that after 220k my toyota needs a little bit of help. I've recently noticed a cylinder misfiring every once in a while while at a stoplight. Well, it's gotten worse and now it sounds like a helicopter when it runs, and the whole car shakes. It went downhill quickly, like in 30 min of driving.

I'm getting a cyl 6 misfire code. It won't rev over 3000 rpm and it gets worse when the transmission is in drive. In neutral it smooths out a bit.

220k on the motor. 2002 tacoma. Automatic.


- spark plugs are old
- plug wires are old
- coil packs are original
- cat was replaced 3 months ago
- maf sensor is clean
- new air filter
- I ran a little seafoam through the brake booster last night, and it actually idled stronger without the booster connected (opposite of what usually happens).
- engine doesn't burn any oil or coolant, it ran strong with no leaks
- the exhaust smells funny. not quite rotten eggs like a bad cat, but it definitely smells bad.



ideas?

Here's what I think it might be:

- coil pack gone bad (this is my current theory)
- old spark plugs
- old plug wires
- clogged injector
- clogged fuel filter (this may be a contributing factor)


I'll be changing the plugs, wires, and #6 coil pack an hour or two. I don't have a compression checker. Anything else I'm overlooking?

 

[TJDukit]

You should be able to test your coil back with a multi-meter. You'd need to find the exact specs for them. If you don't have time to research and test, replace the plugs and wires first. I'm guessing if it's not the coil pack you will likely keep one as a spare anyway.

You could pull your fuel rail and suppply 12v to the injectors to check how strong the spray is.

If the fuel filter is easily accesible I would swap that out just because.

 

[sixstringsteve]

thanks for the help Brian. I have been needing to do the plug, wires, and fuel filter anyway, I guess it's time.

 

[mbryson]

I'd wait on the coil pack until after trying the engine after replacing plugs/wires. You know you need those. Get them done and then see if you still have problems. Even a Toyota that never has issues will need plugs/wires/etc. occassionally (won't it?)

 

[Kevin B.]

Try switching wires and plugs around too, see if you can get the trouble to follow something.

But I think you're imagining it. Everybody knows Toyotas don't break.

 

[sixstringsteve]

I'd wait on the coil pack until after trying the engine after replacing plugs/wires. You know you need those. Get them done and then see if you still have problems.

Good call. I'm going to buy a spare coil pack anyway since I think it's a good thing to have on the trail. Good idea though, I'll do the plugs and wires first. Thanks.

 

[sixstringsteve]

okay these motors have 3 coil packs total. So I'm guessing it's the wires or the spark plug otherwise I would be misfiring on 2 cylinders. Does my logic make sense?

 

[TJDukit]

Your logic seems reasonable.

 

[Spork]

I'd do the plugs/wires and a fuel filter first. If I remember right the 3.4 has the filter on the frame rail so it's easy to get to. A few years back I had something similar and it ended up being bad wires (even though I had replaced them a couple years prior).

 

[sixstringsteve]

Plugs and wires fixed it. Thanks everyone.

 

[TJDukit]

Good deal.

 

[glockman]

Sweet. Glad you got it fixed. Did you get to the rear brakes yet?


Sent from my iPhone using Tapatalk

 

[JL Rockies]

Good thing it wasn't the remote starter.

 

[ricsrx]

Isn’t it nice when an old fashion tune up fixes a motor problem..

 

[sixstringsteve]

Isn’t it nice when an old fashion tune up fixes a motor problem..

I know. I feel like that's NEVER the solution, but this time it really worked out! I had been putting that off for too long anyway. It runs like a top now.

 

[ricsrx]

I know. I feel like that's NEVER the solution, but this time it really worked out! I had been putting that off for too long anyway. It runs like a top now.

I am the same way, dont want to throw tune up money at it if it does'nt need it, look at all the really exspensive parts but realize the tune up needs to be done to work thru the problem...

 

[TurboMinivan]

If I remember right the 3.4 has the filter on the frame rail so it's easy to get to.

Great! Now all we need is a Bic pen.

Glad to hear you solved the problem, Steve.

 

[Rock Taco]

I knew it wouldn't be anything serious. That truck is gonna run forever!

Well it never let me down. I never should have sold it!

 

[sixstringsteve]

I'm hoping to get 500k without a rebuild. I knew it wasn't anything serious either, it runs better than my old 4runner with 60k on it.

 

[Max Power]

What kind of plugs and wires did you go with? I've heard of people having issues with non OEM wires.