ok i replaced the plug wires. when i was putting one on the cap i noticed one was off the cap. if i got the two crossed would the truck still run? because i think i plugged them in the wrong spot. also what is the plug wire diagram for the cap. when i start it, it idles fine , but when i get to about 50mph it shakes really bad around 1500rpm when i'm giving it gas to get up a hill or something. the #8 cylinder missfire is still showing up, but i haven't cleared the computer since i replaced the wires so i think it is still in its memory

 

18436572

 

Does you truck shake/vibrate when it is idling? Check for a burnt valve.

 

nope it idles smooth. it just shakes when i give it gas to move. i let it warm up to running temp and it still does it.

 

Before doing any of this clear your code and see if it comes back as missfire on #8. If it comes back I would start off by checking to see if I was getting spark to #8. If I was getting spark I would then check to see if I was getting a injector pulse at the #8 injector. If that checked ok I would then do a compression test. If that also checks ok and I knoticed the plug was dry while I was checking spark I would prob. condem the injector. . By the way as said before Firing order 18436572. I know this is aolt of if's but you have to eliminate possible causes 1 at a time. .I know some people would approach this a little differently but this I how I would attempt to diagnose it. Good luck.

 

thanks for the info