A while back I posted about having a intermittent miss that would come and go with no engine light, it was a while ago so I can't find the post, but I was told to get rid of the bosch +4 and go back to stock, did that and found that the bosch plugs were TOASTED at only 20,000 miles. Well the problem came back and got so bad that the MIL came on for a cylinder five misfire... THe truck had new wires and now new plugs again so I was thinking the worst but I found a rubbed through ignition wire on the #5 cylinder, can't believe I missed it!!!!! BE CAREFUL OF THAT EGR TUBE, IT WILL BURN AND WEAR THROUGH THE #5 WIRE!!! I covered all the wires in plastic wire loom and tie wrapped them all out of the way, this solved the problem... so if anyone out there is having a buck/miss issue check your #5 plug wire... its a shot in the dark but its real easy to get it to rub on that EGR tube. (Cylinder 5 is the middle cylinder on the driver's side and the EGR tube it connected to the round valve located right where the #5 wire is, in case anyone isn't sure where to find it.)
Hope this is helpful to everyone, if the issue is still there try a compression test and also check your coolant level if you notice it dropping with no sign of it on the ground, bet your intake is leaking which could possible put coolant into the cylinders causing a plug or more to foul out... seen it once or twice, again hope all this helps.
Later,
-Phil

 

Thanks for the information and glad to hear you tracked your problem down.