jukeit

Fixed.

Decided against the dealer diagnostic and went ahead and replaced the coil pack, which resolved the intermittent stutter.

Hind sight signs that pointed to the coil pack....

1. Thin, but distinct vertical black line on the white part of the spark plug.
2. Coil pack boot discoloration. It was a brownish color compared to the black color of the other two.

Thanks for everyone's help on this and have a good weekend. Time to knock back some brew.....

MTL_4runner

Those are definately tell-tale signs of a coil pack boot breaking down.
Glad you got it fixed.

edk007

Hey guys, just wanted to first say thanks for all the info I've received on this site. Don't post here much but plan to more in the future.

I was having very similar problems on my '00 4runner (138000K) and it ended being the coil pack. Engine was stuttering at idle and had very little power until past ~2500 RPM. CEL light came on after a day and codes were P0300 and P0301. Swithed the coil pack on cylinder 1 to cylinder 3 and drove around for a couple days but didn't get any more codes. Finally decided to just try and replace the coil pack. Has been running smoothly ever since.

For a little history, I was having similar problems about a month and a half ago and and decided to just go with the plugs and wires. I had not replaced them since I bought the car at 79000K so they were due anyways. Noticed back then that one of the coil packs was discolored and covered in soot but didn't think much more of it as the plugs and wires did the trick. (Note, the plug on this coil was looser than the rest which I believe was part of the problem). When the misfire codes came up again a few days ago, thought maybe should try some other options first. Finally decided to just try and replace the coil pack though because of the discoloration and misfire code on the cylinder I pulled it from. Also of note is I definitely noticed the distinct line on the inside of the coil boot as well as the side of the spark plug which has been mentioned in other threads. Paid $101 at dealship for new coil pack and still think it was worth it rather than paying around $80 for the full diagnostic.

Hope this helps out if your having similar issues.

edk007

Also, here's a couple pics of the boot. Hopefully you can see the discoloration and the line inside.

Gokumono

Old post, but do you have the link for that?
I looked up championtoyota.com and it came up with webpage that had 3 cities sites listed.

kosmindtrip

ive been having the same problem on a 99 3.4 4runner...i changed out the plugs with ngks changed wires,air filter.... still is studdering oh yea changed out the o2 sensor as well...im wondering if the cat is bad and got hot and burned the o2 sensor up? any thoughts???? thanks... its throwing po302 code misfire detected cy 2

kosmindtrip

are those pics of the coil or ?

Gravehunter

Well this is an old thread brought back to life... but after lots of searching i found this thread and this was exactly what my truck was doing described to a T.

Checked the injector.. cleaned MAF.. pulled the coil packs.. and there it was. that little brown booted.... black streaked B@%^*#D! At least i know what it is now!

Thanks for all the good info to this site... i saved my self some money here!