A couple of weeks ago the #3 plug blew out of my 40K mile 06 4.6. I had no choice at the time but tow it to the nearest dealer for an insert (I have my own time-sert kit coming soon now.) A few days after having the insert installed, the truck started missing really bad while I was a couple hundred miles from home. I limped it to an Autozone where they scanned it and it was throwing #1 and #3 cylinder misfire codes. In the parking lot it just started running fine. The engine light even went off after driving a hundred miles or so. I drove it for another week with no issues. Yesterday I started off on a long trip and it did it again. This time I was able to make it home. The light is still on but it seems to be running ok now. My scan tool wouldn't read the codes so I took it to a local Autozone and they couldn't read them either. It gives an error and will not connect. I checked the OBD fuse and it is fine. Any ideas on the OBD issue and what is going on with the misfires? I'm really losing all trust in the truck. I think it know it just got paid off!

 

I'd take it to your dealer instead of trying to save a buck with the yahoo's down at the auto parts store......

 

I think this is only the second truck after 2003 that has reported a blown plug. Weird

 

Agree 100%. The plug blow out issue was solved years ago. It was caused by too few threads holding the plugs in the heads. About the only way you can blow one out these days is to incorrectly install one. Did the OP change (or have changed) any plugs lately?

 

The plugs are/were the factory installed ones. It only has 40K miles. I had a Ford dealer install the insert and a coil when it first blew out. I wasn't trying to save a buck btw, it happened on a weekend both times. I stopped back at the dealer on the way home from work today. They checked it and said it had thrown a code for #3 cylinder misfire but wasn't sending one currently. They installed another coil (said they have had problems with replacements as of late???), reset the check engine light and said try to bring it in when it is acting up. As far as the plug issue in the first place, they weren't at all surprised an 06 had the issue. I barely drive this truck and it is still like new. I hate having a vehicle that can't be trusted.

 

What engine oil do you run? I have heard if you run too thick of oil it increases cylinder pressure and can cause blowouts

 

I've always used the recommended oil - 5w20 I believe it is. I'm going to change the remaining plugs and make sure they are properly torqued once the weather breaks. I have two 01 Mustang GTs and a 69 Chevelle but can't drive them in these NE Ohio Winters. I totally depend on the F150 in the Winter.