Help - cylinder 4 misfire

[soundmanlpte]

Hello,

I have a 98 4runner, 3.4l V6, 191k miles.

My truck started running really rough, and the CE light came on. It was a cylinder 4 misfire.

Spark plugs and wires are 20k miles old. But I started by swapping out that plug, cleaning MAF, changing air filter, and ran fuel injector cleaner through the tank. No change. I also checked the wires, but they looked fine to me. They are fairly new.

Then I swapped coil packs around, but the misfire remained on cylinder 4. I was down to the fuel injector.

Yesterday I swapped the fuel injector, changed valve cover gaskets, cleaned throttle body, IAC, and intake manifold. At first it seemed to run fine. No misfire. Although in park or neutral, it was idling at 1700 rpm. I assume this is because I cleaned throttle body, and need to add a washer in between the throttle linkage.

But today, the CE light came on again, and it started misfiring. Same cylinder. It seems to run better, but it's sluggish. And it only misfires while in gear. In park or neutral, it doesn't misfire, just revs up real high.

Any ideas?

 

[ajonesnv]

IDK, if this would matter, but have you checked the compression?

 

[Hesk11dog]

Ran into the same problem a month ago. I changed plugs and wires and it got rid of the code but still sluggish at low and high rpms with bad acceleration. A couple people on here have suggested an injector cleaning machine at most local mechanics shop. They plug your vehicle in and run fluid through it. Cost a couple hundred bucks. I'm waiting next month when im home to get mine done, worth a shot.