***misfire help***

[RJLeagles2010]

okay here it is in a nutshell. my engine threw me a P0304 code (cylinder 4 misfire) and so just to be safe i seafomed (into gas tank only) it, changed the all 6 spark plugs and the 3 plug wires that go to the driver side. still getting P0304 so further inspection showed that the connection where the cylinder 4 plug, plugs into the coil pack on cylinder 1 is very corroded. has anyone cleaned this connection? i will have pictures in the morning. the other two connections look great. the misfire is intermittent. i am thinking that this connection is the reason for the misfire can anyone back that and/or tell me if it is possible to clean it to not? :help::mmph:

 

[RJLeagles2010]

bump

 

[LittleCaesar]

Take some emery cloth or the like to it.

I'd try and swap the coil packs first to see if the misfire came back on that particular cylinder. Then report back.

 

[wc11]

I went trough all the same in July.
All plugs, wires etc.
Turned out to be a bad injector.

 

[RJLeagles2010]

Take some emery cloth or the like to it.

I'd try and swap the coil packs first to see if the misfire came back on that particular cylinder. Then report back.

the weird thing is i did move coil packs and the issue stayed in the same cylinder.

I went trough all the same in July.
All plugs, wires etc.
Turned out to be a bad injector.

how did you find out that is was an injector?

 

[LittleCaesar]

OK, then there are three things I think that could be the culprit:

1. As wc11 postulates, bad injector. You may be able to take an ohm meter to the injector to check the resistance. Even with a good ohm reading, it may be bad.
2. Low compression in the cylinder. Run a compression test on all six. Compare your readings.
3. If the O2 sensor(s) or A/F pre cat (Cali spec) sensor is/are original, they may be causing the code.

If I had to pick one of the three, I'd go with the injector being bad, but #2 would be a cheap test to undertake.

 

[wc11]

the weird thing is i did move coil packs and the issue stayed in the same cylinder.


how did you find out that is was an injector?

Sadly, I couldn't figure it out and took it to the dealer.
The truck sounded like a Subaru WRX (which isn't really a bad thing).
Injector #2 (part # 23209-62030) and all is well now.

 

[RJLeagles2010]

here is a pic of the other coil pack plug that is all clean.


this is the dirty one

 

[RJLeagles2010]

OK, then there are three things I think that could be the culprit:

1. As wc11 postulates, bad injector. You may be able to take an ohm meter to the injector to check the resistance. Even with a good ohm reading, it may be bad.
2. Low compression in the cylinder. Run a compression test on all six. Compare your readings.
3. If the O2 sensor(s) or A/F pre cat (Cali spec) sensor is/are original, they may be causing the code.

If I had to pick one of the three, I'd go with the injector being bad, but #2 would be a cheap test to undertake.

i could see #1 and #2 but wouldnt the O2 effect all the cylinders. my friend lent me a timing light and we could see where it was misfiring. i still have it and will try it again once i get the connection cleaned

 

[RJLeagles2010]

New Info

okay after a while the misfire had stopped and now its back again and alot more constant. but i found that it only misfires when im just hold it at a constant speed if i accelerate to where it downshifts or just leet off the gas completely and coast it stops. i did do the intake box mod so could the one vac line that was on the box effect it?

This is where it was.

and this is where it is now.

not my pictures but its the same placement.

 

[BrianSD_42]

Dude part of troiblwshooting is following a methodology to isolate and eliminate problems.

I wouldn't mess with your intake until you've eliminated other possible causes first.

That coil pack connection that is all burned looking, yeah that is a concern.


1. Is the coil pack that looks corroded also the one connected to CYL 4?


2. DID YOU DO the compression test?

i did do the intake box mod so could the one vac line that was on the box effect it?

3. Just curious but What the s%&$@# mod involves moving vac lines ?around?

 

[Supermoney]

When diagnosing a misfire I start like:

Spark plugs and wires
Coilpacks
Injectors

Then O2 sensors and others, etc

 

[4x4mike]

We had a friend have a similar problem recently. His coil pack looked the same, 'dirty', as yours did. At around 50% throttle the pack would arc outside of the spark plug tube and around that dirty contact.

We moved the coil packs around and the arcing followed so we replaced the faulty coil pack. All his other packs had much cleaner looking contacts. FWIW he had the misfiring for probably 500+ miles if not more and there were no codes.

 

[RJLeagles2010]

Dude part of troiblwshooting is following a methodology to isolate and eliminate problems.
1. Is the coil pack that looks corroded also the one connected to CYL 4?
2. DID YOU DO the compression test?
3. Just curious but What the s%&$@# mod involves moving vac lines ?around?

==
1. Yes
2. What is a compression test? im new to working on my vehicle and in general.
3. I just followed directions and the guy that wrote it did not mention any ill effects. and if the vac line was the issue wouldnt it have started right away? this is where i went. (((Intake Silencer Removal Mod - 3rd Gen 4Runner (2000) - YotaTech Forums))) i just re-read it and saw the mistake on the vac lines. going to fix that asap. :redbrick:

I have looked at getting the AirRaid Jr intake tube because the current rubber one is starting to have surface cracks.

When diagnosing a misfire I start like:

Spark plugs and wires= check
Coilpack
Injectors

Then O2 sensors and others, etc

i am going to find a electronics person to see if the wiring is bad anywhere.
if it were the injectors wouldnt it be a constant problem instead of an off and on one?

We had a friend have a similar problem recently. His coil pack looked the same, 'dirty', as yours did. At around 50% throttle the pack would arc outside of the spark plug tube and around that dirty contact.

We moved the coil packs around and the arcing followed so we replaced the faulty coil pack. All his other packs had much cleaner looking contacts. FWIW he had the misfiring for probably 500+ miles if not more and there were no codes.

iv moved my coil packs around but the issue always stays ar cyl. 4

 

[Doc2012]

3. If the O2 sensor(s) or A/F pre cat (Cali spec) sensor is/are original, they may be causing the code.

Please, for the love of all things holy, explain to me how this would cause a misfire code?

Not trying to be a smart ass, but I've had a 3&4 misfire code for over a month now. I've done plugs, wires, compression test, the works, and I still can't figure it out.

I guess I can try moving the injectors around again, but it didn't seem to make any difference before. Part of me is thinking it might be the damn Knock sensors, since they're located on 3&4, but I'm lost as of right now....

 

[SV_Dude]

Revived the thread... Bump!

 

[BrianSD_42]

[MENTION=86991]RJLeagles2010[/MENTION]

2. What is a compression test? im new to working on my vehicle and in general.

For you, me, and anyone without a good set of tools, a compression test is where you find a mechanic who works on Toyotas / Japanese cars and tell them "I need a compress test on all 6 CYL with a printout" followed by "I will pay $50"

Plenty of mechanics should be able to do this no problem.

If you have friends or family then maybe they can do it.

ALTERNATIVELY you can start a new thread "help I live in xxxx city and need help with a compression test on my 3rd gen"

Perhaps someone down the street is on T4R.

 

[kolelt]

Same problem here. I have misfire in cylinder 3 on my 97 6cylinder. It started as a minor misfire. Barley noticable. I replaced the sparkplug wires, after two weeks the carstarted chocking at steady 50+ mph. Very annoying as if someone is bumping into you. Then check engine light came on. Brought it to my friend who checked the code. He said cylinder 3 is misfiring. I told him I noticed a spark escaping at night when giving it throttle. He said replace the coil. So I replaced the coil. Still same problem same misfire same choking feeling at high speeds. The idle is ok. Before the coil the idle was shit. Now it's better but still misfiring on start and at high speeds. I'm so annoyed so pissed. Today I will try replacing the sparkplug and cross my fingers that it will fix the misfire. Can anyone help ?

 

[stackz]

or just go to advance auto, autozone, oreilly auto parts or any of the similar type auto parts chains and rent a compression tester...

you get all your money back when you bring it back to them. pull all the plugs out and disconnect the coils. screw the compression tester in the hole you want to check and crank the engine over 3 times. you want to hear the compression stroke around 3 times, then stop and read the gauge.

then let the air out the check valve and do a double check. then check all the cylinders. when you're done, post up the numbers and return the tester and get your money back.

I'd also do a leakdown test if you have access to an air compressor.

 

[stackz]

Same problem here. I have misfire in cylinder 3 on my 97 6cylinder. It started as a minor misfire. Barley noticable. I replaced the sparkplug wires, after two weeks the carstarted chocking at steady 50+ mph. Very annoying as if someone is bumping into you. Then check engine light came on. Brought it to my friend who checked the code. He said cylinder 3 is misfiring. I told him I noticed a spark escaping at night when giving it throttle. He said replace the coil. So I replaced the coil. Still same problem same misfire same choking feeling at high speeds. The idle is ok. Before the coil the idle was shit. Now it's better but still misfiring on start and at high speeds. I'm so annoyed so pissed. Today I will try replacing the sparkplug and cross my fingers that it will fix the misfire. Can anyone help ?

did you see the spark at the coil itself? if so then likely the coil was breaking down. pull the plug and look for burning down the side of the porcelain. a coil breaking down will find the least resistance path to ground which can be the metal plug base. once the porcelain is scored enough, the plug is trash.