Im getting the below misfire codes, usually happens when first starting up truck, if engine is already warm and i clear the codes and start it up and drive it again this issue doesnt seem to happen. Truck does run slightly ruff on cold startup but not to the point of it stalling or anything, truck has lost of power, doesnt smoke or leak anything. Codes are below
P0300 - Random Misfire
P0305 - Cylinder 5 Misfire
P0308 - Cylinder 8 Misfire
I have ran fuel injector cleaner through truck - Didnt Help
I have changed spark plugs to Champion with proper gapping, noticed old plugs were all over the place with wrong gappings but didnt notice anything strange with old plugs, oil, white plugs etc etc
I changed distributor cap and rotor, all plugs looked fine when i did this, made sure plugs were put back to the proper terminals. (BTW the digram to do this blows because if you notice cylinder 2 and 7 are straight forward not like the pictures online show where the cap is slightly twisted!!!)
After doing all the above i am still having the same problem! Thought about changing out spart plug wiring but dont think that is the problem.
Noticed today there is vaccum line broken (bottom left of throttle body - looking at it from the front, not sure what this is for or if it could be part of my problem?)
Any other ideas of what i should check or replace. Possibly coil pack?
Please respond with any ideas, thanks in advance