fillups56

first time poster but long time forum lurker. i have a 97 T100 SR5 3.4 with 81,000 miles that is throwing codes for a cylinder 4 misfire. i have replaced spark plugs, plug wires, and coil pack and still have the miss. the only thing that i can think of that is left is a bad injector but i just wanted to make sure i wasn't missing anything else that it could be before tearing the intake off to get to the injector. if it sits over night i can go crank it up and drive it for 15-20 min. and everything runs fine but it will eventually start missing again and then it will do it everytime i crank it up unless it sits for a long time. looks like if it was a bad injector then it would do it all the time to me but i could be wrong. i just wanted make sure there wasnt anything else it could be (crank sensor, cam position sensor, etc.) before digging in. anyone had this problem before? thanks for any help.

SC T100

Check your grounds just to be sure. Also, make sure the plugs you put in were dual ground NGK or Denso...T100s (and any 3.4 5VZ apparantly) don't like the bosch plugs.

tommytuttle

I'm having a similar issue and just searching right now for some ideas. Anyone know of a write up for removing the injectors?

fillups56

i went ahead and changed the number 4 injector, seems to have done the trick. ill know for sure with some more driving time. as far as removing the injectors this is the best write up i have found on it. its actually a pretty easy job. i believe you can just swap them out without taking off the plenum if it is a bad number 1,3,5 injector. you have to remove the plenum to get to 2,4, and 6.



https://www.yotatech.com/forums/f2/f...es-how-109389/

SDMF

Guys I've got the same issue. Changed the wires twice, plugs (yes the right ones), injector, swapped coils (still #4 misfires). Checked the ECM w/ voltage checks. Dry compression test was good. I've got spark. Maybe the harness for the injector? I tried to listen to the injector but its near impossible to get to with the stethoscope, because of the plenum. Anything I'm missing? My compression tests were good and all were about the same +/- 5 so I wouldn't think my valves would need adjusting. Timing from the ECM. Maybe it's not sending a firing signal? F-me. What a pain in the arss this has become. I've read all the threads and I don't think anyone has this much trouble with a misfire.

BamZipPow

I wonder if you could put a tester bulb on the suspect injector connector to see if it lights up or not when it's activating the injector?