well my truck is throwing a random missfire on the 8th cylinder. i cant hear or feel it when its idling or driving around. i have changed to coil, spark plug, and the wire. i have no clue what else to do or look at...

thanks robert

 

You could try swapping the injector with the one next to it and see if the misfire moves to that cylinder...

 

Yeah man, sounds like a faulty injector to me too!

 

i will buy one tomorrow.

 

Double check the electrical connection at the injector first, they've been known to come undone...

 

I work at a GMC dealership and we see alot of injectors plugged that are in the ends of the fuel rail on returnless fuel systems. if you remove the injector you should be able to see alot of gunk in the screen where the fuel comes into the injector

 

i went and bought a new fuel injector and the truck ran good for a day. now its doing it all again. when ever i floor it in first and it shifts into second it does not wanna go over 4000rpm but if you keep it floored or let out and floor it again sometimes it will go away. it almost sounds like it hitting the rev limiter.

 

have you checked fuel pressure? replaced fuel filter?

 

the motor only has 32000 miles on it. can i check the fuel pressure with hp tuners?

 

You need a manual gauge connected to the fuel rail to check pressure