2007 Ford Explorer 4.6l 3v Missing/Bad Coils

[rowekmr]

I just got a 07 Explorer Ltd with the 4.6l 3v engine that sounded like a lawn mover when running. The CEL light on with codes P0171 Bank 1 system lean,P0300 random misfire,P0304 Cyl 4 misfire, P0305 Cyl 5 misfire, P0355 Ign coil 5 malfunction.

I have owned a few Fords with mod engines and know the coils go out with time but in the past I had the stealership do them but this time I decided to try to tackle it myself. I got 2 motorcraft DG511 coils and replaced the #4 coil but when I got to #5 it was disconnected from the engine harness and the coil was pulled up out of the hole partially. I replaced that coil also and when I started it the idle was still bad at first but it slowly cleared itself and eventually idled smoothly.

I drove it for 20 miles mainly city driving with no issues but noticed on highway when cruising that the engine missed when I gave it a little gas to accelerate. After that driving it there was no codes so my question is do I need to change another coil? If so how do I now try to find out which coil is bad?

I saw on YouTube that many people put dielectric grease in the end of the coil boot but I couldn't find any at home when I did this. Could that be the problem, should I buy some and use it on the 2 I installed?

Also when I installed the coils they did not sit all the way down on the plug I had to tighten the hold down screw to get them to seat completely, is that normal?

[rowekmr]

I didn't check the plugs. Not comfortable trying that on my own. I might have them done at shop.

azrving wrote:
How were the plugs? The grease can help the boot come off easier during removal. I would checked/replaced all the plugs and anti seized the threads.

[rowekmr]

I do know that the spark plugs can break when trying to remove them which is why I didn't touch the spark plugs.

Get into...do you mean getting the truck or trying to replace the plugs? If things get over my head it will go to Ford I was just trying some DIY'ing.

dodge guy wrote:
You changed the coils but not the plugs?

You may want to search the internet for 3 valve triton spark plug issues. then sit back and ponder your what you got yourself into!

Best to take it to the dealer and let them do it. and yes it will be expensive, but better than you having to deal with it!

[azrving]

dodge guy wrote:
You changed the coils but not the plugs?

You may want to search the internet for 3 valve triton spark plug issues. then sit back and ponder your what you got yourself into!

Best to take it to the dealer and let them do it. and yes it will be expensive, but better than you having to deal with it!

I was being nice.......lol

[dodge_guy]

You changed the coils but not the plugs?

You may want to search the internet for 3 valve triton spark plug issues. then sit back and ponder your what you got yourself into!

Best to take it to the dealer and let them do it. and yes it will be expensive, but better than you having to deal with it!

[troubledwaters]

If you clear the codes after you change the coils, the PCM will continue to monitor the misfires and a scan gauge will tell you each cylinder and how many misfires it had. Just find the cylinder (or cylinders) with the considerably more number of misfires.

[azrving]

How were the plugs? The grease can help the boot come off easier during removal. I would checked/replaced all the plugs and anti seized the threads.