So had a misfire changed the plugs no fix, now just changed all the cops. My truck runs fine on idle but when you drive it runs like crap. Throwing codes p0351 p0355 p0356. I clear them and let it run at idle for a half hour and no codes, the n drive and it throws the same three codes again, I need some direction on tbis. I read a lot of possibilities but don't know where to start.

 

What engine and what year?

 

What brand cops and plugs?

 

Assuming you're not using some cheap eBay-grade coils, I'd ask what codes you had prior to changing the coils and plugs. Nothing wrong with aftermarket as long as it's a reputable brand.

Plugs shouldn't have anything to do with these codes. But hopefully you used an OE style plug such as Motorcraft or Autolite XP/HT (depending on if you have the 4.6L or 5.4L). Based on context clues, I'm assuming you don't have the 4.2L V6.

Many of us are happy to help, but we need more details.

If you don't have a scanner or don't remember what codes were present before, I'd swap the coils around and see if the codes follow the coils or stay with the cylinder. If they follow the coils, you got some crappy ones. If they stay with the cylinder, suspect wiring, ground, or PCM issue.

 

I have a 2006 with 5.4l I put granitelli coil packs in and autolite plugs, I think the problem is the plastic connectors though, just noticed that they keep vibrating loose some I'm going to replace those three and post the resaults.I can not remember the orginal codes .

 

Your problem may be the Granatelli COPs. Many have had problems with them.