Here is the story. I changed the plugs a few weeks ago and of course #3 (middle back) stripped out. I went and got a heli coil kit from car quest. I had to tap out the like 15 times before I got it. used the medium insert and put it in as far as it would go. It goes in all but the first row of tangs. Everything ran fine for 2 days now I get random multiple misfires, truck runs like crap and shudders also it drinks gas like you wouldnt believe. Do you think that #3 has something to do with it? Ive been reading that that problem is probably a vacuum issue and rarely a plug and wire issue. I have looked for a vacuum leak but everything looks attached. imposable to remove the egr valve to check it. One other thing, the wife overheated it a month ago, if that helps.

 

The overheating might have been a big factor why the misfires happen. I noticed that on my car before and the mechanic told me that overheating is one of the causes and i had to replace the EGR valve.