Yesterday after I started my truck it started running very rough and it started vibrating pretty bad. After about 2 miles of driving the check engine light came on. I took it to Autozone and checked the code and it said that cylinder 4 and 7 were misfiring. I had all of the spark plugs replaced less than 2 years ago. It has 251000 miles on it. Does it sound like I need to replace the coils? If so is that difficult to do? Thanks for the help!

 

How many mile on the current plugs? If over 60K, need to change them. If over 40K consider changing them. (Make sure you use MC brand)

Change the fuel filter and clean the throttle body, but your problem is most likely the COP's. Very easy to change just make sure you have dielectric grease to seal the plug to boot and boot to coil interface.

 

The plugs have less than 20K on them. Is it common for the COPS to go out all of the sudden? Prior to last night I haven't had any problems

 

The Cop's on these motors go bad for no reason. Often they have a low grade miss that only happens under load (hills, towing...) New cops go bad as well, so if you're replacing 2 cop's buy 4 new ones, you'll need them.

Rockauto.com has some of the best prices if you're replacing them all. Some guys by them on Ebay, but lately the supply quality from China is poor.