Cylinder 3 misfire BAD!!!!

[RPTFE00]

Hey guys, I have a 2000 2.7l I have been having a sight rough idle, and very intermittently would feel like I am running out of gas, like a stuttering. I had done a backprobe with a voltmeter and determined my MAF was going out due to the signal going dead even with slight throttle. So, I'm waiting for my next payday to pick one up, and this morning I start driving to work and it is doing the stutter, but this time it stays, and then i get a flashing check engine light (I know, big misfire, doing damage) so i slowed down and limped to work. i concluded it wasn't my MAF causing this due to checking all things associated with it on the scanner. Here is a list of things i have tried today.

-swapping cyl 3 and 2 injectors - misfire stayed on 3
-swapped coils - misfire stayed on 3
-pulled spark plug, to check for cracks, abnormal burning, or any looseness, i did notice the plug was wet, no noticeable smell. (maybe thats it?)
- pressure test on cooling system, no leaks outside of head, or inside of cylinder.
-vacuum test, results were steady vacuum, but slightly low due to practically dead cyl.
- checked for signal from ECU to coil, and its present.
- block test and passed.

I am a little confused. and im exhausted thinking about it, and trying to figure it out. has anyone experienced this, and had it fixed? I'm stuck.

OH! and there are no codes on even though the whole truck is shaking.
i think thats it, but i cant remember, it was a long day. thanks guys!!!!

 

[SilverRidgeRunner1]

What was the compression on Cylinder 3 AND was the fluid oil or fuel or maybe coolant.

 

[RPTFE00]

What was the compression on Cylinder 3 AND was the fluid oil or fuel or maybe coolant.

compression im not too sure, however i have somewhat ruled out any major mechanical issue considering when it was just very intermittent it would come, and then go. and run like a champ. and thats what im confused about, it didnt have any distinct smell. definitely didnt smell like coolant or have the potency of fuel. i smelled the plug and idk if you have ever smelled like wet dirt? but it was that smell.

either tomorrow, or monday im going to do a leakdown and compression test just to get that out f the way, but the testers i have were not at work. im totally stumped, and my brother who is a master tech isnt here, he is trying to help but he cant feel or hear it so its tough.

 

[SilverRidgeRunner1]

Sounds like what you maybe having is what is referred to as Pre-Ignition and Detonation it happens when the carbon build up on a piston heats up and ignites the fuel before the spark occurs giving u a similar feeling of a miss fire. Also I have heard of the 2.7 having compression issue to a point where u would have a no start issue occurs but thats a little extreme.

 

[gamefreakgc]

Fix the MAF first. That tells the ECU how much air is coming in and then adjusts fuel. With that being broken as you suspect, there's no way to accurately diagnose the misfire, or even fix it.

 

[SilverRidgeRunner1]

Typically the issue seen with a faulty MAF would be hard starts, engine stalls over all (Not on just one Cylinder) Engine hesitates at speed or drags while under a load or idle. Hesitation/jerking at Acceleration OR engine hiccups. Typically u would also see excessively Rich or lean indling. Lots of unknowns at this point on data. Could u fill us in on some of the codes stored during your check maybe one of them holds the key... Its rather interesting your getting a misfire just on Cylinder 3 and not a Multi cylinder misfire. I am rather curious on the wetness on the plug and the compression on Cylinder 3 compression ALSO the OMH of Cylinder 3 injector and coolant temp sensor.

 

[St Runner]

Start with a basic tuneup. Put brand new plugs in, new air filter and clean the maf. I am not sure if the 2000 2.7 has four coils or two coils and plug wires.If you have two coils change the plug wires. if you have four coils, swap the 3 coil and see if the misfire follows. As has already been stated you need to check the compression esp in the #3 cylinder. A wet plug on #3 sounds like an individual cylinder problem, better to start with the basics then chase the misfire monster around randomly

 

[RPTFE00]

Typically the issue seen with a faulty MAF would be hard starts, engine stalls over all (Not on just one Cylinder) Engine hesitates at speed or drags while under a load or idle. Hesitation/jerking at Acceleration OR engine hiccups. Typically u would also see excessively Rich or lean indling. Lots of unknowns at this point on data. Could u fill us in on some of the codes stored during your check maybe one of them holds the key... Its rather interesting your getting a misfire just on Cylinder 3 and not a Multi cylinder misfire. I am rather curious on the wetness on the plug and the compression on Cylinder 3 compression ALSO the OMH of Cylinder 3 injector and coolant temp sensor.

Only code I have ever had is a 420 code, cat code. And that has been on and off for a while, but I have zero codes when this happened. Still no light, or codes, pending or otherwise. I haven't physically tested the coolant temp sensor, but on data stream, there seems to be no fluctuation, or dead spots in the graph of the ECT. Today I plan on doing a compression test, leak down test, and testing resistance on the injector, I did swap the 2 and 3 though and the misfire stayed.

Start with a basic tuneup. Put brand new plugs in, new air filter and clean the maf. I am not sure if the 2000 2.7 has four coils or two coils and plug wires.If you have two coils change the plug wires. if you have four coils, swap the 3 coil and see if the misfire follows. As has already been stated you need to check the compression esp in the #3 cylinder. A wet plug on #3 sounds like an individual cylinder problem, better to start with the basics then chase the misfire monster around randomly

The MAF is clean, I have a new air filter, and the plugs have just about 20k on them. This engine has the coil on plug system so all 4 coils. I have already swapped coils from 3 to 4, with the misfire remaining on 3 then back, and then I swapped 2 and 3 coils with the misfire remaining on 3. I'm testing compression today, but I highly doubt this is a mechanical issue, considering how sporadic the problem was before this happened.

 

[SilverRidgeRunner1]

Only code I have ever had is a 420 code, cat code. And that has been on and off for a while, but I have zero codes when this happened. Still no light, or codes, pending or otherwise. I haven't physically tested the coolant temp sensor, but on data stream, there seems to be no fluctuation, or dead spots in the graph of the ECT. Today I plan on doing a compression test, leak down test, and testing resistance on the injector, I did swap the 2 and 3 though and the misfire stayed.




The MAF is clean, I have a new air filter, and the plugs have just about 20k on them. This engine has the coil on plug system so all 4 coils. I have already swapped coils from 3 to 4, with the misfire remaining on 3 then back, and then I swapped 2 and 3 coils with the misfire remaining on 3. I'm testing compression today, but I highly doubt this is a mechanical issue, considering how sporadic the problem was before this happened.

It seems like your all over it something going to stick out pretty soon I predict. With a little diag u will pin point it without replacing a bunch of parts to fix..

 

[RPTFE00]

Here's the update, I was about to do the compression test, but thought "before I get it hot I'll swap the plugs and see if one fouled" so I swapped from cyl 3 to cyl 2 and alas!!! The misfire moved! So my #3 plug fouled and was not firing any longer. So I ran it and did the rest of the tests and she was okay. I guess the plug was bad, so tomorrow imp info to the dealer to pick up a set of plugs. Makes me happy it wasn't anything huge. And I'm glad I stopped driving it immediately.
I know I'm going to get ridicule saying "why didn't you do that to begin with" and I know. Haha
I just figured that with Denso platinum set it should not only last 20k. But I guess you get some bad batches like with any part.

 

[SilverRidgeRunner1]

Here's the update, I was about to do the compression test, but thought "before I get it hot I'll swap the plugs and see if one fouled" so I swapped from cyl 3 to cyl 2 and alas!!! The misfire moved! So my #3 plug fouled and was not firing any longer. So I ran it and did the rest of the tests and she was okay. I guess the plug was bad, so tomorrow imp info to the dealer to pick up a set of plugs. Makes me happy it wasn't anything huge. And I'm glad I stopped driving it immediately.
I know I'm going to get ridicule saying "why didn't you do that to begin with" and I know. Haha
I just figured that with Denso platinum set it should not only last 20k. But I guess you get some bad batches like with any part.

Welp that's the purpose of diag/troubleshooting a guess can cost a lot of money but proper diag will solve the one problem and resolve. congrats on the discovery. A tech in a dealership can't give u a list of things to replace to try and solve the problem he has to test all the possible causes and fix it. The strangest job I've come across was this 4RUNNER with a multi cylinder misfire. Everything checked out and was in proper standing according to Toyota spec. The problem ended up being the A/C compressor kicking on and off causing the ECM to throw a Multi cylinder misfire.