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Waiter21 · 05-18-2016, 07:44 AM

I went for a test drive after pulling out of storage, filled the tank up with gas. On the drive, the engine seemed to be missing every now and then. I pulled the codes and seen misfires on several cylinders, 1,3,5,6,9

I cleared the codes, went for a short drive, after 10 minutes, the codes all re-appeared. (only misfires, no other codes) I did not look at mode 6 data.

History - I bought this MH used a couple years ago and before we used it, I went throuh it and made sure all the maintenance was up to date (fluids, filters, brakes, etc)

I installed new plugs, but reused the original COPs (Coil on Plug) but installed new boots and springs. The spark plugs were torqued to 160 inch lbs. The MH now has 70,000 miles

Last night, I pulled the #5 COP, I don't see any obvious signs of arcing on the boot or the body of the COP. I'll pull the plug tonight and look at it.

My plan right now is simply replace all 10 plugs and COPs. I'll mark the COPs that are giving the misfire and save all the parts for spares.

mrt_1111 · 05-18-2016, 01:23 PM

Might be bad gas. I would check fuel pump pressure and replace fuel filter. What are the odd of the COPs going bad at the same time. I would think it would be something in common with all the cylinders. How many miles does it have? How long has it been in storage? If I remember correctly gas start to go bad after three months without adding stabil or such.

mrt_1111 · 05-18-2016, 01:37 PM

Never mine about the miles I see it

Waiter21 · 05-18-2016, 02:04 PM

Been in storage since late Jan. Gas should be ok, I filled it up this weekend (40 gallons in 70 gallon tank)

I also run the genny every couple months when I have it stored.

I think if it was fuel related, it would be random, but the same cylinders show up.

I read in several threads on the Ford forum that they don't recommend replacing boots and springs, as the replacements have a very high failure rate. Evidently when the old boot and spring is removed, it can scratch or damage the coil, and then this is where the failure / arcing starts to happen. This is the one common factor on these failures, all the boots and springs were replaced.

10 new coils (with boots and springs already installed) cost $60. I'm going to put in new plugs at the same time, even though I just replaced these less than 15,000 miles ago.

Waiter21 · 05-19-2016, 06:35 AM

I pulled all ten plugs last night - I didn't see any obvious signs of the misfire problem on any of the plugs.

I installed 10 new plugs, Autolite APP-103. Just a thin coat of anti-sieze on the threads and torqued them to 160 inch lbs.

I'll put the new COPs on when I receive them.

NOTE -

I blew all the spark plug wells out real good before I started loosening the plugs. However, when I tried to loosen two of the plugs, #6 and #8, I couldn't get the socket to fit over the plug. (scratching my head)

I finally got a light down in the hole so I could see what was going on. I could see what looked like a small piece of gravel sitting on top of the metal part of the plug. This was preventing the socket from going down all the way on top of the plug.

I used a long thin screwdriver to move/wiggle/loosen the stone, and blew air down in the well. After a couple attempts, the stone finally came out and I was able to get the socket onto the plug.

RECOMMENDATION - Don't remove any of the plugs until all of them are loose.

Waiter21 · 05-19-2016, 01:43 PM

I replaced all 10 COPs, putting a little silicon grease on the inside of the boots before installing them.

It started right up. I cleared the codes and went for a 30 minute test drive, various speeds, loads, etc. No codes..

There wasn't any hard core smoking guns, I couldn't see any signs of arcing or arc tracks on the boots, the plugs looked ok...

mrt_1111 · 05-19-2016, 03:20 PM

Maybe arcing through the gravel. Had alot of dirt/dust when I changed mine. Glad it's fixed. Be safe.

RodK · 05-20-2016, 10:26 AM

Sometimes the coils just break down inside with no visual signs. I replaced all 10 of mine last year and it is running smooth as silk.

Waiter21 · 05-20-2016, 12:09 PM

Rod, yes, 16 years old --- #5 would set a misfire code almost immediately after clearing it.

I got a $2 rebate on each of the plugs so all 10 COPs and plugs ran right at $75 ($5 for the COP and $2.50 for the plug). The cost savings in fuel on a trip to the west coast will pay for that.

I also had a chance to test my chirp-chirp-chirp serpentine belt fix.. more on that in another thread.

RodK · 05-20-2016, 03:26 PM

When mine was acting up, I had cyl 10 misfire. I switched it with another one and my misfire moved to that cylinder. I replaced all 10 as mine is a 1999 and all original. I got all 10 off of ebay for the same price as 2 locally.

mrt_1111 · 05-25-2016, 11:48 PM

Quote:

Originally Posted by Waiter21

I replaced all 10 COPs, putting a little silicon grease on the inside of the boots before installing them.

It started right up. I cleared the codes and went for a 30 minute test drive, various speeds, loads, etc. No codes..

There wasn't any hard core smoking guns, I couldn't see any signs of arcing or arc tracks on the boots, the plugs looked ok...

Was the the silicon grease the dielectric kind?

Waiter21 · 05-26-2016, 05:00 AM

Yes, on the dielectric. You don't need big gobs of this stuff. just enough to put a very light coating on the inside of the boot so it won't stick to the plug.

Don't put it on the plug. use a small cotton swab and wipe it on the inside of the boot.