had this truck for a while, it will missfire around 2200-2500 RPM and has a slight fuel knock here and there at lower rpm and gentle throttle. i have a edge 3 POS chip and if i use it then the missing is around 1500-2300. i have put all new injectors in. have tried a different ICP IPR and IDM with no difference. the only code i can ever pull is for the left UVCH however when it missfires its not on one side of the engine its the whole thing. when it happens all sensors will flatline (when watching with a scanner) i have also tried to tighten grounds but nothing makes a difference.

 

Remove the chip completely of the pcm and see if it keeps doing it.

 

the chip is completely removed

 

Have you replaced the UVCH and pig tails?
And also check the 42 pin connector to see if there's any cahffed wires.
What about the CPS has it been changed?
Also what brand of sensors you buy? Anything not OEM will cause all sorts of problems.

 

If all sensors go dead like that then to me I'd think the PCM is losing power.
Are you sure your miss isn't the engine dying and coming back ?

 

yes the miss is essentially the engine dying then comming back very suddenly. also not often but sometimes on the highway the engine will compleatly reset. it will shut off and just coast with the wait to start light on then after 5 secs itl come back (truck is manual btw) im about to replace UVCHs and il check again around PCM for bad wires. just tired of throwing money at this

 

The PCM is losing power for some reason. I'd start with the ignition system

 

my ignition switch was intermitently shuting off the engine, had to replace solved the problem ,, noticed it from the volt gadge jumping ,, jiggled the key and it would do it ....

 

Glad you solved your problem. Props to Mike.

 

I have checked the wires around the PCM and towards the injectors. Nothing looks chaffed or grounded out. Im gonna try swapping CPS and PCM with another truck and see if that does it. I cant see it being the ignition cylinder because of the chip changing the missfiring range

 

Check the tin nut on the back of the IPR. Make sure it's not loose. Also, check the pigtail that plugs onto the IPR and the wires leading up to it for damage.

 

I can unplug the IPR and it doesnt really effect it. Obviously changes the running condition but not the actual missfiring

 

Did you unplug the ipr or icp?

 

I have had both unplugged il check again anyway though. Been kinda busy lately

 

With the IPR unplugged it won't run at all.