another misfire question

[jatibb]

99, 3.4, 5spd, 4wd. cold start, runs fine. stop for a bit, restart when still warm, misfire. not bad, but def there. if i rev up while driving, ce comes on flashing, then when i slow down it stops, misfire still there. scan gauge stays plugged in all the time. stores a #3 or 4 misfire. i replaced the coils, plugs, wires awhile back, last 5k miles or so ( it doesnt get driven much), replaced again, ngk dual tip plugs, ngk wires, denso coils, still doing it. just weird for cold to be ok, then starting warm starts an issue.

 

[brillo_76]

99, 3.4, 5spd, 4wd. cold start, runs fine. stop for a bit, restart when still warm, misfire. not bad, but def there. if i rev up while driving, ce comes on flashing, then when i slow down it stops, misfire still there. scan gauge stays plugged in all the time. stores a #3 or 4 misfire. i replaced the coils, plugs, wires awhile back, last 5k miles or so ( it doesnt get driven much), replaced again, ngk dual tip plugs, ngk wires, denso coils, still doing it. just weird for cold to be ok, then starting warm starts an issue.

If compression is all good across cylinder 3 and 4 as I just check them all to verify... I be looking for vacuum leaks and possible failing injectors on those cylinders as I believe I am fighting a cylinder 6 misfire which didn't go away when I swapped the coils.. I need to investigate further on one of my rigs as well.

 

[jatibb]

im thinking injector from other searches. when cold starting/driving it runs great, for long after up to temp. only after sittting and restarting before full cool down does it misfire, and not badly, driveable, no back firing, no overheating. gonna swap fuel filter and see if it helps. bout to have valve cover gaskets done so would be a great time to put new ones in

 

[Ben Dejo]

im thinking injector from other searches. when cold starting/driving it runs great, for long after up to temp. only after sittting and restarting before full cool down does it misfire, and not badly, driveable, no back firing, no overheating. gonna swap fuel filter and see if it helps. bout to have valve cover gaskets done so would be a great time to put new ones in

Same symptoms as my 99 with a bad injector. I didnt have a ODB2 scanner at the time, but you may want to check the STFT and LTFT in the freeze frame data for the misfire. If one of those is -/+20 for the fuel trim, that may help point to a failing injector. 2 of the GB remanufactured injectors I bought leaked, which turned out not to be remanufactured but some no-name knockoffs. Didn't pay to cheap out for me. In hind sight, I wish I hadn't sent my original injectors in for the core deposit back. I could have just purchased a rebuilt injector from a better shop or one from YotaShop. Gotta see that Aisin logo molded in the plastic to know they are the ones Toyota used. I did get a set from MotorWest eventually. I would have preferred to have the Aisin ones installed, although they do have an issue with the solenoid. Plenty of info out there on injectors.

 

[Endlessblockades]

99, 3.4, 5spd, 4wd. cold start, runs fine. stop for a bit, restart when still warm, misfire. not bad, but def there. if i rev up while driving, ce comes on flashing, then when i slow down it stops, misfire still there. scan gauge stays plugged in all the time. stores a #3 or 4 misfire. i replaced the coils, plugs, wires awhile back, last 5k miles or so ( it doesnt get driven much), replaced again, ngk dual tip plugs, ngk wires, denso coils, still doing it. just weird for cold to be ok, then starting warm starts an issue.

'Warm misfire' condition is nearly ALWAYS worn-out injectors, but hey, at least you've got some fresh spark distribution stuff. And back up stuff. That's what I tell myself. I like the injector kits from MotorWest Performance. OEMs are an arm and a leg IIRC.

Edit - don't forget the gaskets and banjo washers. 3.4 stuff is at the bottom of the linked homepage.

 

[Buckaroo]

99, 3.4, 5spd, 4wd. cold start, runs fine. stop for a bit, restart when still warm, misfire. not bad, but def there. if i rev up while driving, ce comes on flashing, then when i slow down it stops, misfire still there. scan gauge stays plugged in all the time. stores a #3 or 4 misfire. i replaced the coils, plugs, wires awhile back, last 5k miles or so ( it doesnt get driven much), replaced again, ngk dual tip plugs, ngk wires, denso coils, still doing it. just weird for cold to be ok, then starting warm starts an issue.

Would look at the injectors as others have said. To verify, you can swap 3 and 4 with others to see if misfire follows. You could also check resistance cold (which will likely be good) and then heat them up in an oven and see if the resistance changes.