"Misfire in Cyl. #3" Trouble Code

H

Her4Runner

New member
Chasing this intermittent prob. on our 2000 3.4L...

Truck runs on what seems like 5 cylinders - rough idle & shakes all the way through the RPM range.

What I've done:

--installed new Denso plugs less than a year ago; pulled #3 plug & it still looks new.
--just installed new plug wires yesterday.
--listened to each pass. bank injector w/ stethoscope & all "tick' consistently;
--swapped coil over #3 cyl. to #1 to rule out a bad coil pack; reset ECM to clear trouble codes - same CEL comes back..

Funny thing is that each time I change something, truck runs smooth as silk until you shut her down. Start it back up & problem returns!

About to pull #3 coil pack connector to see if it runs any worse; if not, it would seem I have an intermittent short somewhere in the wiring harness that feeds that coil pack. Will report findings.

I'm not new to auto mechanics so this has me quite frustrated. Any other ideas, similar encounters?

Her4Runner
 
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Im having the EXACT same problem with my 97. It idles rough and shakes through the entire rpm range. Code keeps coming up with cylinder 2 missfire. Ive replaced the plugs, and the wires. The injectors are new. Im at a loss, just like you, because I'm not new to this stuff and I'm out of ideas. Ive had four mechanics tell me different things and none of them have solved the problem. Some of them worked for a few minutes, but after driving, the roughness returns as well as the check engine light.

Update me if you figure it out haha.

PS. Does your check engine light flash if you accelerate too hard? Mine does, and that CANT be good.
 
kustomkhaos said:
Have you tried disonnecting the neg cable for a few mins so it can relearn its values?
Click to expand...

I've pulled the ECM fuse (which accomplishes the same thing - resetting the computer) after every change I've made.

Her4Runner
 
UPDATE:

--triple-checked all underhood electrical connections, incl. coil pack & fuel injector harnesses.
--triple-checked all vacuum hoses.
--swapped #3 plug w/ a known good one.
--cleaned MAF again, just to rule it out.

Start truck & it purs like a kitten. Drove around for ~10 miles, putting it through all its different paces. Ran perfect. Parked it & returned 15 minutes later to resstart it, & problem reappears. Shite! After sitting overnight though, GF drove it to work & it ran normal.

So, could a bad/stuck injector act like this? What about a break in a wiring harness somewhere? Due to the intermittent nature of this, & the fact that the DTC is so specific, I really don't think this can be a mechanical or "hard part" failure such as a bad cam lobe, valvetrain etc.

I'm at a loss...

Her4Runner
 
The first time I took it to a mechanic he did a compression check, and it came back with good compression, so its not a burned vavle. I think Ill be taking it up to URD tomorrow since I have their fuel kit/injectors/plugs/computer etc. to have them look at it.
 
UPDATE

Thought I'd update, for others' poss. info...

Problem turned out to be a BAD INJECTOR in cyl. #3. Couldn't pinpoint it until recently when symptoms became constant, having been very intermittent before. Confirmed power & pulsewidth at the injector plug connection. Put a stethoscope on that injector while running & no "tick" at all; all othes ticked consistent w/ each other.

Thought about replacing all 6 w/ a set of reman'd (cleaned & flowed) injectors off of eBay, but decided to just replace the bad 1 w/ a genuine Toyo part (~$155.) Mechanic said he'd do it for 1 flat-rate hour ($70.) Thought that was fair since they didn't charge me for either of the 2 "diagnostic" sessions, & I would've pd. them for at least 1 hour had I decided to do the job myself.

Hope this helps! Fhornerguy - did you ever figure out your problem?

Her4Runner
 
i know this thread is old, but i have the EXACT same problems as described. 1999 4Runner 3.4V6. Misfire in cyl. 3, hesitation on acceleration all the way up the RPM range with the check engine light flashing. The check engine light will go on and off on the highway, too. And it stays on while driving around town...(30-50 MPH). I replaced the plugs, wires, cleaned the MAF, and injector cleaner. I listened to the 3 injectors on the passenger side and the 1 injector that i could get to on the drivers side without removing the intake, and they all sounded good and consistent. All the wiring looks good to the injectors that I can see as well. Did replacing your number 3 injector fix your problem? Or was it something else?
 
It's standard to start with the coil packs. Cyl #3 is the middle one on the passenger side. Swap that coil with one of the adjacent ones and if the miss moves to cyl #1 or 5, you know it's either the coil pack or the rubber boot that feeds the plug directly underneath. I would then try just changing the boot because it's a lot cheaper.

If that fixes it, get new boots for the other 2 coil packs. If it doesn't fix it, replace just the one coil pack. (I think I replied to another question exactly like this today, haha). All this is if the miss moves. If it doesn't, then you are looking at either an injector, a valve train issue, or something more remote like a blown HG. you aren't missing any coolant, right?
 
Ive bought a brand new coil pack and the problem went away for a month. The parts store swapped it for free. It did the same thing a month later. I took the pack back to the store and told the guy what was happening. He hooked me up with the better coil pack they offer instead of the one that i got twice already. Ive swapped it to other cylinders, and it acts and drives the same way, same code.

Id be willing and able to change the fuel injector if i could narrow it down to just that, but from what im gathering from the forums, there might be other things that are easier to look at that might be the culprit.

And no, not missing or leaking coolant. No squeaks, leaks, knocks, or smoke. The engine is quiet as can be while idling.
 
The injector is a good possibility, but not a sure thing. Testing the voltage doesn't mean jack if it's clogged up so even if it tests ok, it doesn't always mean it is. If I were you, I would probably just swap the #3 (which is easy since you don't have to remove the intake plenum for that side) and see if it takes care of it. You could always clean your original and sell it if swapping doesn't fix it so you wouldn't be out too much $$. Also, replace ALL the o-rings (upper and lower) for all 3 injectors on that side and apply a little Vaseline or motor oil so the rings won't tear when you put them back in. Re-using o-rings can cause leaks.
 
Same basic problem but #3 and #4 with random misfire codes.

I know this is an old post but i've got the same problem, same symptoms, but it's throwing a misfire code on cylinders 3 and 4. It also has a code on random misfires.

I'm going to change the plugs tomorrow, inspect the wires, and test the resistance on the coils. I'll try changing the coil on cylinder 3 to 5 and recheck the codes to see if it changes the misfired cylinder. If this all checks fine I'll inspect the injectors.

Other than this do you have any thoughts of whether this could be something even more than just electrical/fuel since 2 cylinders are misfiring? It all started when I was driving on the highway going about 70mph for about an hour into a drive.
 
greensr5 said:
I know this is an old post but i've got the same problem, same symptoms, but it's throwing a misfire code on cylinders 3 and 4. It also has a code on random misfires.

I'm going to change the plugs tomorrow, inspect the wires, and test the resistance on the coils. I'll try changing the coil on cylinder 3 to 5 and recheck the codes to see if it changes the misfired cylinder. If this all checks fine I'll inspect the injectors.

Other than this do you have any thoughts of whether this could be something even more than just electrical/fuel since 2 cylinders are misfiring? It all started when I was driving on the highway going about 70mph for about an hour into a drive.
Click to expand...

If your electrical/fuel is good...I would start checking your hardware. Possibly have a bad cam lobe, burnt valve, broken spring, rocker arm, or someother valvetrain problem. I apologize, I just got into Toyotas...so I can say if one or more of the above parts are a known problem child. But, if you have a miss...these items should be checked. Good luck...
 
It could always be the spark plug arching off the block. It will make a tapping sound. If that's the case you need to replace the insulating sleeve that goes into the block on whichever cylinders are misfiring. Other than that, injector, or perhaps coil pack. If you change your plugs look for black streaks running down the porcelain potion, that is the indication of the block arch.
 
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Anyone find solutions to this? I just had the same issue, misfire in #3, swapped all plugs/wires/coils/#3 injector, same issue. My mechanic ran a compression test, sea foamed it, checked all of the things I did to make sure I did them correctly, and is getting the same thing, he is stumped and suggested it could be a bad valve spring. He's keeping the truck another day to play around.

WTF? Is it odd we all have the misfire in cylinder 3? Coincidence?

Thanks!
Reid
 
"Misfire in Cyl. #3" Trouble Code

If electrical and fuel are fine, then head gasket? I got bad misfire on cyl #2 and turns out my gasket blew and my head was cracked. There is a test that a mechanic can do that tests for coolant in the cylinder. That will tell if your head gasket blew
 
Issue was resolved. The "new" fuel injector I put in turned out to be bad. Put in a 3rd injector and all is well. Thankfully not the head gasket!
 
fhornerguy said:
Im having the EXACT same problem with my 97. It idles rough and shakes through the entire rpm range. Code keeps coming up with cylinder 2 missfire. Ive replaced the plugs, and the wires. The injectors are new. Im at a loss, just like you, because I'm not new to this stuff and I'm out of ideas. Ive had four mechanics tell me different things and none of them have solved the problem. Some of them worked for a few minutes, but after driving, the roughness returns as well as the check engine light.

Update me if you figure it out haha.

PS. Does your check engine light flash if you accelerate too hard? Mine does, and that CANT be good.
Click to expand...

Sounds like what was wrong with mine, except I was only misfiring above 3000 rpm. Cylinder 5 was arcing to the engine head instead of sending current to the spark plug. Changed the coil pack boots and the problem went away.

Check the spark plug of the affected cylinder for carbon tracking.
 
2000 2.7L 4Runner RWD Automatic

Sorry to bump an old thread, but this is happening to me and I couldn't post a new thread. Anyways I was getting a Misfire on Piston 2 and a Random Misfire error code. I purchased new plugs recommended in the manual and replaced them (Noticed oil? on the old sparkplug ceramic, will post pics as soon as I'm home). Replaced spark coils and boot(I have coil on plug version). Also noticed that while turning in the plugs, I'd hand tighten then used a torque wrench to 14 ft-lbs. On plug #2, right after I'd hand tighten, it felt like less than a quarter turn would get 14 ft-lbs while all the other plugs would get around 1/2 to 2/3's of a turn before reaching 14 ft-lbs. Does anyone have any idea what's going on? Did I strip or damage the threads? Started the engine up, noticed it was still rough on idle, drove about 10 miles and the check engine light blinks, during moderate acceleration and I think 5th gear when I'm going 70mph at 1.5-2.0 rpm it shakes vigorously, I have to let go of the gas and accelerate and keep it at 2.5k rpm to subdue it to an extent.

Any ideas what actions I should take next? I'm on a tight budget and would like to do what I can.

Much appreciated.
 
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