Cylinder 6 misfire

[ShaneRC51]

Someone help me figure this out. Truck has been running great until yesterday morning. Developed a sudden misfire. Auto parts place scanned it and came back with cylinder #6 misfire.

While I was in the parking lot, I swapped coils from cylinders 1 & 3, reset ECU, and scanned again. Still came back #6 misfire. I swapped a new spark plug in #6, but no change. At this point I'm leaning towards fuel injector.

This morning I pulled the intake manifold off and dug my way down to the fuel rail on the driver's side. Pulled injector #6, and took it with me to the parts store. I bought a BWD injector for $126. It looks identical to the one I pulled out of the truck.

Get home and install the new injector with new o-rings for all 3 injectors. Get everything buttoned up, and it still misfires. I pulled the spark plug wire off of #6 and held it near to block - it's making pretty electrical arcs. So it's not the coil, it's not the plug wire, and it's not the spark plug. The injector is the only thing it could be, right??? I just put a new one in there! What are the chances I got a brand new - bad - injector?

I don't know what else to do except pull it all back apart again. My multimeter has a dead battery. Tomorrow after work I'll replace it and try to test my old - and new - injectors to see what they register. This sucks...

 

[stir_fry_boy]

Someone help me figure this out. Truck has been running great until yesterday morning. Developed a sudden misfire. Auto parts place scanned it and came back with cylinder #6 misfire.

While I was in the parking lot, I swapped coils from cylinders 1 & 3, reset ECU, and scanned again. Still came back #6 misfire. I swapped a new spark plug in #6, but no change. At this point I'm leaning towards fuel injector.

This morning I pulled the intake manifold off and dug my way down to the fuel rail on the driver's side. Pulled injector #6, and took it with me to the parts store. I bought a BWD injector for $126. It looks identical to the one I pulled out of the truck.

Get home and install the new injector with new o-rings for all 3 injectors. Get everything buttoned up, and it still misfires. I pulled the spark plug wire off of #6 and held it near to block - it's making pretty electrical arcs. So it's not the coil, it's not the plug wire, and it's not the spark plug. The injector is the only thing it could be, right??? I just put a new one in there! What are the chances I got a brand new - bad - injector?

I don't know what else to do except pull it all back apart again. My multimeter has a dead battery. Tomorrow after work I'll replace it and try to test my old - and new - injectors to see what they register. This sucks...

Let the truck run at night in the dark with no lights on, can you see #6 wire arcing? Sometimes they only arc in a certain position where the insulation is broken.

 

[TheDurk]

Might be time for a compression check to rule out a valve or ring issue before tearing it down again.

 

[ShaneRC51]

New coil pack on #3. No change. However, now the scanner is picking up misfire on #3 & #6, and mass air flow something...

Ready to pull my hair out. This has to be something simple. WTF...

 

[ShaneRC51]

Maybe it's just early in the week, but I'm a little disappointed that I haven't received many replies (but thanks to you guys who did).

So today I drove it to work, and she was running worse than ever. I spent a little more time on it in the O'Reilly Auto parts parking lot. When I got there, I was telling the guy there about what I've been through so far. He scanned it again, and now it's coming back with codes for misfire on #6, misfire on #3, mass airflow, and TPS. Before I was just getting a code for misfire on #6, not all this other crap. We decided to try a new coil on cylinder 3 (that feeds #6). He told me that if it didn't work, I could get my money back ($80!). Pulled the intake off, swapped coils, reset the ecu, and..... still missing.

Pulled the new coil back off and put the old one back on. Scanned it again, and now it's only throwing a code for misfire #6.

Let's recap: So far I've tried swapping coils, new spark plug, new fuel injector, holding the #6 plug wire to the block to see good arcing, new coil on #3. All to no avail. The guy asked me if I've tried new plug wires. I told him no, since I grounded the wire and it looked good. He says that's really the only thing I haven't replaced, so let's try that.

Bought a new set of plug wires ($40), swapped just the wire for #3 --> #6, and started the truck.


IT PURRS LIKE A ****ING KITTEN!!!

All this time the only F#CK!NG thing wrong was a bad spark plug wire going to #6. I'm out $126 (injector), $4 (sparkplug), and $40 (wires) = $170 + tax all over a shitty little $10 wire.

Damn I'm glad it's fixed...

 

[LookAtThatDog]

I'm glad this worked out for you. I rarely hear about people having misfires due to wires - it seems like replacing plugs/boots/wires is the first step in fixing the problem but usually the last thing that helps.

 

[ShaneRC51]

The wires on it aren't that old. Maybe 3 years? And I tested the #6 wire by pulling the wire off of the spark plug and holding the tip near the engine block. It arc'd nicely, so as far as I knew the wire was good...

 

[WEIMY12]

Looks like your misfortune my be my benefit, I've got the same problem with Cylindar 6 throwing a misfire code. But I also had a P1135 A/F Sensor code. A/F sensor replaced, plugs aren't that old, and previous owner said wires were new but that was 2 years ago, 170k miles, maybe time for new plugs, wires, boots just because... before I go into anything really expensive.

 

[Jonathantharris]

Two days ago, I had the same issues as ShaneRC51. Misfire on Cylinder 6. We figured the simplest fix would be to change the plug. No change with a new plug. Pulled the new plug and confirmed firing on the engine block. Spark appeared good. Next, I checked the compression compared to other cylinder. Compression was the same. Next step was a fuel injector. I was able to find an injector in stock at the closest part store. $130 and I thought I would be done with this misfire. Got the injector installed and issue remained.

THEN I SAW THIS POST!

Picked up a new set of plug wires and BOOM! We are back up and running! Turns out the boot on Cylinder 6 had an arc where it makes contact to the spark plug. It was firing out the side of the boot below the valve cover, but of course when I held it to the block, it no longer had the same path to ground. Never thought to check there and would have saved and a headache! Thank you for this post and I hope it will help others to know it worked for me as well!