Truck was missing really bad when I bought it but they were driving it before it was detailed and it was fine. I thought it started because the engine was steamed and I believed water got around the plugs. I had 1/4 of a tank of gas at this time after two days it stopped and it was the same day I filled it up. I'm back at 1/4 of a tank and it's missing gain but only at a certain speed, 40-45. Was the deal with this? Is it the gas at the bottom of the tank ? The engine hasn't been wet so it can't be water around the plugs...

 

90% chance its a bad Coil. finding out which one exactly is the fun part

 

Would that still make it only happen at a certain speed. It only does it at like 40-45 and like 1200 rpm

 

Yup that is the exact point a bad coil causes a mis. It usually wont throw a code or anything so its really hard to pin down which one. It usually is best to just replace all 8 though because once one goes the rest are usually on there way out

 

Ok ima bug you some more lol, why does it not do it all the time at that speed only sometimes?

 

And what's the cost of replacing coils ? I would have it done, I'm not very mechanically savvy . And should plugs be replaced also? Sorry for the trouble just want this fixed ...... It there anyway it could be the gas towards the bottom?

 

Also truck has 143 xxx miles all original motor and trans

 

Im not gonna sit here and BS you like I know exactly what I'm talking about but heres what I've gathered about the topic. Apparently the COPs in our trucks are known to short out, but not completely fail. So at certain times under the right conditions the coils like to short and cause an intermittent roughness and a mis. You can sometimes gas it hard through the speed range and completely avoid the mis. Its really weird and I don't exactly know the physics behind it. Also OEM coils can cost like 80-90 per cop new but you can get a set of weaponx coils for like 300-400 depending on which ones and they are supposed to be as good if not better then factory ones. As far as changing them its no more difficult then spark plugs they simply come off with one bolt I believe and a clip.

 

Thank you for your help I really appreciate it

 

Also avoid the ebay special coils, some people don't have a problem but a lot of people say they are terrible