[DuncanMaynard]

I'm ready to pull out what's left of my hair. My n/a 2000 3.3 with 123K miles has had a miss for a while. It started as the multiple cylinder misfire. I changed the plugs, checked resistance on the wires, renewed the dielectric grease on the wire connections, changed the fuel filter, which looked like it had mud in it, changed rotor, cap and upper distributor bearing. Cleaned the MAF sensor. After those attempts, I was down to "just" a cylinder 3 misfire, which makes me think I was chasing more than one problem and corrected the others.

Changed the cylinder 3 injector. Nothing changed. I still have the cylinder 3 and perpetual knock sensor codes.

I didn't use NGK plugs, but the ones I replaced before the code also weren't NGK. So if you're going to scold me for not using OEM plugs, you better give me a reason only the one in the cylinder 3 hole is misfiring. It's definitely getting spark. I checked it with an ignition spark tool. Just for grins, I'll swap the cylinder 1 and 3 plugs today.

I haven't checked compression, but there are none of the other signs of a leaking head gasket.

I can't believe the coil could cause a single cylinder misfire, but I'll listen to reason.

I haven't checked fuel pressure, again thinking that couldn't cause a problem with a single cylinder which has a new injector.

Can you help a brother?

 

[XterraD4u]

If it isn't the wire, spark plug, or injector, the only thing I can say is compression...try seafoam, through the brake booster vacuum line, it might knock some carbon off of the valves helping them to seal, if that doesn't work, then I'd run compression checks and make sure nothing major is going on

Darin
01 Xterra SE 4x4
COMING SOON:
Intake mod, timing belt, hoses, belts
Wish list:
PML, EFan conversion, shocks, 32" tires, and eventually UCA'S

 

[DuncanMaynard]

Forgot to mention I already did the Sea Foam treatment, having learned about it here. I guess the compression check is an easy task, so let me at it!

But if anyone has another idea before I get back, I'm all ears.

Thanks.

 

[DuncanMaynard]

I never swapped the plugs in cylinders 1 and 3, but was going to do that yesterday morning after checking compression. I pulled the number 3 plug and smelled victory. It had the narrowest gap I've ever seen. I checked it at 0.015! How did THAT happen? I had checked the gap on the new ones before install. I didn't drop the plug, and if I had, would have checked the gap. It seems to me it would take a pretty hard knock to bend the electrode that far, so I don't think it happened by jamming the plug against the head trying to find the hole. Mystery of life.

Runs very smooth now and no SES light. My red face is almost gone.