This is not about my truck. A friend of mine called asking a few questions this afternoon. He has a 2004 F150 with 116,000 miles. He has a rebuilt tranny and has never had the plugs changed. Last week he had his alternator replaced after it left him dead on the road. He said that the truck will "shake and shutter". While it does this it looses power. This has been happening while under acceleration. He said that letting off the gas will stop thiss problem. The issue is intermitant and not all the time. The check engine light does not come on and there are no codes being thrown.

My first thought was a misfire or possibly a bad coil pack. He said that when his Expy had a bad plug or coil pack it would immediately throw codes and engine lilghts.

My buddy is pretty tough on this truck. He owns a landscaping business in costal SC and frequently overloads the truck by pulling more than it was rated to tow. This is why he had to have the tranny rebuilt. He said that he never had this issue prior to teh replacement of the alternator.

Any thoughts or suggestions?

Thanks guys

 

With 116k, he's way past the spark plug change interval.

 

Yeah that's what I said. I convinced him to shop around for a place to change plugs and coil packs. I have read some other posts where people had similar issues and after plugs, packs, and sometimes a PCM flash the problem was fixed.

 

Coils at retail are going to be a small fortune. The factory 3v coils seldom fail, but he definitely needs plugs. If he does need one or more coils, buy a full set of DG511's from Uneek or Global on Ebay, the set is about $115.