Getting very bad misfire and my programmer says Random misfire on cylinder #3. Have not been able to get my compression tool to go into the threads because its a piece of crap. I swapped the plug wire out with a brand new wire, still the same problem. Getting the blinking SES light when it gets bad, lower the RPM worse it gets. Feels AND sounds like its lost a cylinder or two. Lack of power. No backfires or popping, but once it drops down into 4th gear it chugs and vibrates very bad. Also have not been able to check the fuel injector. What else could cause this?

 

Also have brand new iridium plugs and coil packs in it and they look brand new still. Problem just started happening. Truck was running PRIME.

 

I'd guess wire, coil, injector, intake gasket. I would be swapping coils and injectors next.

 

coil, wire and intake gasket are out of question so its gotta be fuel injector, and if not what else would cause a misfire like this?

 

Just because the coil is fairly new dosent mean you shouldn't check it. Why do you rule out the intake gasket?

 

if you suspect the injector you can swap it out pretty easily since you gotta pull the fuel rail off.

 

If nothing else works remove the cam cover and look for a roller follower off or broken valve spring.

 

Well because if it was 1 of the coil packs i wouldnt have power on all 4 cylinders and they would all be misfiring, its only cylinder 3 which and i hope to HELL its nothing in the head or im going to be so pissed off. They were just rebuilt with all new parts, ported out with brand new cams...And i ruled the intake gasket out not only that its brand new long with every single gasket and seal in the motor and was installed 100% correctly but wouldn't cause me to have a misfire one 1 specific cylinder. The entire timing would be off. I am getting perfect spark to the and through the spark plug. That doesn't mean i dont appreciate every second you spent helping me in this thread dude cuz i do, its just far more serious then that.

 

I am going to take it to a performance shop tomorrow. Normally i would have solved this problem already but this is just far far worse then anything i have ever experienced. And i have experienced every suggestion noted by everyone and this cannot compare. I am assuming its internal, top end in the heads or blown out rings.

 

brand new comp cams behive valve springs but the roller followers were not. Maybe with the cams and ported heads and all the other bolt ones they gave out?

 

Well theres only one way to find out and thats to pop the cam cover and have a look. Might want to have them perform a leakdown and compression test on the entire bank as well. This way you will eliminate the possibility of a mechanical problem. Good luck.

 

Even though the spark plugs are relatively new there can be a bad one every once in awhile......

 

If you are sure of the plug and injector I agree with the above and would do the leak down test, that will tell you if you have a ring or valve issue

 

What exactly is a leakdown test. I am sure its not the coil packs, plug or wire, havent switched out the fuel injector or did a compression test yet but im working on that tho lol. Would it be okay to take a 19lb 4.6 injector and swap that out temporarily just to see if its an injector. Only way i know how to test them ha! So whats a leak down test?

 

Swap injectors like you did plugs

Leakdown test http://www.carcraft.com/techarticles...ter/index.html