Hi, im new to the forum. I really need the help of this forum. I have a 2004 Nav, and I have been to the dealer and 3 other auto places, were my Nav was put on a machine. Out of the 4 , none of them can find any codes, or whats causing my rough idle. For months, I thought it was bad gas, so I started using Chevron and Shell, no help. Yesterday, I put the truck on what they say is a 15k computer. The computer couldn't pick up any thing, but the service tech says he knows a coil is is missing. I said lets fix it, he said he would have to check every single one of them, wich would be pricey. He also said to drive it until it gives you a code, then we can pin point the coil. My question is there any other way to find this bad coil, im not comfortable driving my truck like this. Plz HELP!!!!

 

You need to connect a scanner that reads live data while you drive. It will count misfires and give you an indication of which cylinder is the problem.

 

Were can I find this scanner?

 

By buying, borrowing, or renting one.

 

I have seen a few Fords that the missfire monitors were shut down . A Rep told me it happend sometimes with problem vehicles . They would NEVER set a missfire code or turn on the CEL . You may have one of these . A good shop will still have ways of finding the miss . Using a scope on each coil , A pressure transducer in the tail pipe and the proper scope software , and a few other tricks . Good luck !