Misfire

Reply Subscribe

Thread Tools

Search this Thread

Apr 10, 2011 | 01:45 PM

Treker58

Thread Starter

Tuned

Joined: Jan 2011

Posts: 365

Likes: 1

From: Massanutten,VA

Misfire

Though that I would ask people here with experence, been getting things done to the X I bought a month ago-ball joints-sway bushings- rotors/ pads-rear hatch lock etc,etc. I started to check the coil boots the other day but couldn't check them all because it started to rain. Checked 7 of them, the #6 cylinder boot has a couple of cracks around the bottom of the boot but nothing that when all the way through, none of the boot had any grease in them which I was going to do had it not start to rain. About the misfire it seem to only happen out of overdrive, if it misfires and I take it out of OD it stops,it also seem more prevalent after damp weather but can be sure of that. As I have said I have never noticed the misfire out of OD, hoping this is a coil problem and not transmission, fluid level is fine but the fluid also seem new, transfer case fluid is also new. I know that it had a service at 103K new air filter, there is also a notation that the fuel system had been service anyone have a similar problem, Thanks Guys

May 5, 2011 | 06:02 PM

willieyp

Freshman User

Joined: May 2011

Posts: 36

Likes: 0

From: Cape Cod

Ok.... Lots of variables! I've been through the ignition system a thousand times until I finally got it figured out. First of all, which engine do you have? I have a 6.8 v-10 gas. I have had the same prob. I found that after the engine spitting out a plug and installing a helicoil, the coil came loose and the plug went too far in and melted the electrode. re-measured the threads and mega lok tighted the new one back in with bosch +4's. It's been great since. MUST DO'S.... Di-electric gel everything! Dont stop at the hard plugs.... fix them all! Put neversieze on all threads! TIGHT IS TIGHT AND TOO TIGH IS ****ED! The little connectors for the injectors and the cops are very fragile and make sure they are tight. If the retention clips are broken, use small zip ties to hold them tight! I took liquid electrical tape and coated the joint between the cops and the boot to make sure they werent arcing out. All this equals pleasure!

May 5, 2011 | 08:16 PM

wpnaes

FTE Chapter Leader

Joined: Nov 2010

Posts: 30,586

Likes: 1,234

From: N. IL

Some ideas: check for a code from an OBDII reader - that will tell you whether a cop is bad.

Boots with cracks: I don't like any, just bite the bullet and replace them all.

Does it happen while coasting in neutral? I'm beginning to think an Ex with stock leaf front springs on a USA paved road (meaning no maintenance since the economy went to heck) feels like missing. Maybe I'm crazy

May 5, 2011 | 09:13 PM

EXv10

Post Fiend

Joined: Mar 2009

Posts: 11,798

Likes: 14

From: Mt. Shasta California

A misfire can happen at low rpms only when in hi gear and slow speed which makes it feel like the tranny or a bad u-joint and the reason yours does it when it rains is because moisture gets in the holes. Squeeze the boot ends together and if you see ANY cracks replace it. I would replace all of them and put heavy grease and a lot of it around the tops of the new boots and a tiny bit on the end of the spring so water won't get back in there..Regular axle type grease might soften your rubber boot tops over time but it beats having water in the holes.

May 6, 2011 | 08:12 AM

Treker58

Thread Starter

Tuned

Joined: Jan 2011

Posts: 365

Likes: 1

From: Massanutten,VA

Sorry should have said that it is a 2003 6.8 V10. Have had it scaned at Advanced but since there is no CEL they say that they can't read anything. Yes the misfire seems as if it is a coil is failing( as it doesn't do this every day, may misfire today and then not for severl days) or at least shorting out need to check the rest of the coil boots to eliminate that part of the problem. It seems as if the previous owner was trying to figure the problem out also as there is a sticker in the engine compartment saying the fuel system was serviced at 103K.

May 6, 2011 | 08:58 AM

EX40

Senior User

Joined: Jan 2006

Posts: 157

Likes: 0

From: Gary, IN

Did you/they actually hook up the scanner? I had no CEL and just got a reading on #10 misfire. Scan it anyway if you haven't. Takes away the guesswork. I'm replacing my plugs and boots plus the one cop this weekend.

May 6, 2011 | 10:16 AM

Treker58

Thread Starter

Tuned

Joined: Jan 2011

Posts: 365

Likes: 1

From: Massanutten,VA

They hooked up the scanner, I watched them. Turned it on and said pass, I belive, not sure what type of scanner it was it was at Advanced Auto. I figured that even if it wasn't throwing a CEL that the onboards would list it as a misfire and or a failing COP