Hi guys, have a 1997 4Runner 3.4L V6. Two weeks ago I completed a cross country trip but while in New Mexico I filled up with 85 octane a few times. (I usually put in 87 octane.) Then a few tanks of gas later my engine threw a cylinder 3 misfire code. Checked the sparkplug/coil and all is good on that front.

Since then, the engine idles rough (it's vibrating hard not revving up), poor fuel mpg, noticeable lack of power when accelerating. It drives "rough". However all of these problems start and stop seemingly almost like every other day and they either all appear together or none of them do. Comes and goes.

Is it possible/probable that that 85 octane gas clogged up the cylinder 3 injector?? Now it needs to be replaced? I poured some injector cleaner in the tank but it has not stopped the problem from reappearing.

Thanks!

 

Just how does it come and go completely random??

Is it fine at starting but gets worse after a few miles.

If it was me the first thing would be to change the fuel filter.

When was the last time it was done??

If dirt got through the filter it would more then likely have effected more then just one injector.

 

"Is it fine at starting but gets worse after a few miles."

Yep, that happens

 

You have a fuel injector that has failed. Mostly likely you also have P3XX code. Do a quick search and you'll see this issue is pretty common on 96-98 5VZ.