dphelps1964

I installed new motor craft spark plugs into my 4.6 2V. Had no problem what soever with replacing them, just their location was a bit of a pain in the a**. I have drove it about 15 or 20 miles since then and I have noticed that it will have periods of real rough idle, and then go back to normal. I figured I would wait it out to see if the computer just needed to be reprogrammed since I unplugged the battery to change the plugs. Not the case. This morning while I was driving the check engine light came on, so I imagine it is more than likely a misfire. I am going to plug it in and see what code it is throwing and see what the problem is. Anybody have any problems with something similar to this?

barriosman

Did you replace the boots or the coils too? How many miles on the engine?

dphelps1964

I did not replace the boots or the coil overs. Just the plugs. It has 97,000 on it.

barriosman

Rule of thumb (from what I have learned on this forum) is to at least replace the boots too. I replaced the coil pack, but some just do the boots. Over time, the boots deform to the shape of the plug.

dphelps1964

Alrighty. Thanks for the feedback. Would the boots have anything to do with a plug misfiring?

barriosman

Yes, a bad COP could cause a misfire. Also, did you double check your plug gaps. I've also seen guys on here with issues like yours because they didn't correctly torque their plugs.

dphelps1964

I checked my plug gaps and everything but I believe I know what could he the problem. My buddy helped with the process and I remember him saying that he accidentally ripped off part of the boot. Could this cause it to be shortin to the head before it reaches the plug. I found a nice write up on yahoo. Here's the link:
http://m.voices.yahoo.com/ford-f-150...t-7970264.html

barriosman

I would definitely think so. Just replace the boots...one at a time if you have to. Boots, alone are about $13 each. The whole COP would be around $50-60 each for genuine Motorcraft parts.

Oilfield_Trash1953

Kinda dealt with the same thing. But I'm in a lot worse shape. Had plugs and everything changed 2 months ago with 111k miles while I was at work in ND. Come back home truck runs great. Came home this time and it's missing again. Took it to my mechanic friend and used his computer and it said cylinder one misfire. Changed coil again and still misfiring. Took coil off and noticed the plug was loose. 2 turns by hand and plug came out. Now dealing with a hole in the piston. Guy won't stand behind his work. Plug doesn't look 2 months old to me.

dphelps1964

I think the boot should solve the problem. Luckily I think it tore on one of the front plugs. Gonna hope it's not a COP. Thanks for all the good feedback!