I've had this truck for a couple years now and I've just now started to work on it due to other projects. Well here's my problem I have replaced spark plugs wires sensors and everything else to do with the fire and what not I can't think of what it is I rented a timing light and its good I've heard somewhere it could be a flat exhaust lobe on my cam? Could that be causing this and also has straight pipes. Please help I need it .

 

Can you confirm this is how you have the plugs wired.

 

Let me make sure again about to run out there

 

All plugs are right where they should be

 

Did this problem just start out of the blue or has is been slowly getting worse?
Even with new plugs and wires you could be getting cross firing between the wires if they are routed near each other, cylinders 5 and 6 are prone to this because the follow each other in the firing order. If you can get the truck running in the pitch black and turn all the lights off you will be able to see any arcing between wires or to the block. If that checks out OK then I think your next step is a leakdown test to see if you have any bad valves.

 

It has done this since I bought it in 2011 it runs and idles fine just when you put it under a load it starts popping.

 

And I moved the wires apart and still doing it

 

I'll be doing a leak down test at my buddys house I don't have a air compressor

 

Alright just got the leak down test done its between 160 and 175 sorry for the late reply just got home from traveling so what's the verdict never done a test like this before.