Hey I have just recently finished up my 4runner and I have been noticing a weird problem. So the story is, the 4runner runs great most of the time but sometimes it will run rough and misfire. This is the pattern I have noticed is when i first drive it in the mornings it runs awesome, but say i drive it for about 10 minutes go to a store and come out a bit later it starts to run not so great. It will continue to run bad until it sits for several hours. I have tried restarting it, resetting the ecu. still runs bad but like i said if it sits for several hours it is fine again, until i stop and come back out.

About a week ago i was driving it on a 4 hour trip and it was running not so good and about half way through the trip i felt like a surge and it was running great. So i am not sure what is going on here i am stumped.

I have read on a couple forums of people having similar issues and it turning out to be an injector but i cant figure out which one if any is struggling.

I have wired in my OBD2 and am not throwing any misfire codes.

Any ideas on where i should start on trying to figure this out?

Thanks everyone

 

this is on the 3.4 4Runner? i had a similar issue on my 3.0. it ended up being timing, vacuum and the throttle position sensor. its fixed now.

 

Yes sorry it is on my 90 4runner with a 3.4. Hmm that is interesting. Thanks for the information.

 

Double check your spark plugs. I had the same prob. Plugs fixed it.

 

Hmm I will take a look at them. I replaced the wires and plugs not even a month ago, but i did get them off of eBay so who knows. The plugs are denso and the wires are NGK. Has anyone had issues with this setup? I might just go get facotry wires and plugs and see if that helps. Thanks for everyones quick responses

 

Check you injector connectors. I had a similar if not same problem on my old 3.0L due to a loose connector (broken tab)

 

Use an OBDII scanner and get the code(s).

 

I have already checked the codes, which was stated in the OP. I figured it out. It was just a bad injector. Thanks for everyones input.