Hey all, i have a 05' lariat screw 4x4 with a random cylinder misfire. Got two codes on different days. P0300 & P0307? Bought it used and dealer said they did a tuneup.. Is it worth replacing all 8coil packs from ebay $150 for all? How can i tell if dealer changed the plugs? Local advance auto wants $42 per pack?

Please help

 

The dealer might or might not have changed the plugs. And if they did, they might not have used Motocraft plugs. I know I had misfire trouble on mine with Autolites till I changed back to Motocrafts.

You may want to try and pull one plug and have a look before you buy coils. When it's random, it's less likely to be the coils. If you're going to replace coils, folks (including myself) have had good luck with Uneek off ebay. About $110 for a set of 8

http://www.ebay.com/itm/360401087174

SP515 plugs are only $8 each at O'reillys

On another note, not to say your dealer is like this, but on my truck, the previous owner had the plugs changed at a dealer. They had used Autolites. But even worse, when I swapped them out, I found out that cylinder 4 was NEVER changed and had the original plug (which broke on me, of course ). So they told the owner it was all changed, charged him for it, and he wasn't any wiser.