Plug misfire

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Oct 4, 2006 | 12:40 PM

maceslin

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Joined: Aug 2003

Posts: 28

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From: Chesapeake, VA

Plug misfire

02 Explorer 4.0 L 6 cylinder
Just changed plugs last weekend with 125K on the old ones, looked pretty good except for gap.

Installed new plugs and now running very rough. Popped twos code this morning for Number three cylinder misfire and something about number three at low RPM.

Suspect that I have a cracked plug on number three cylinder, any other ideas.

So that I don't have to pull all plugs can someone confirm that number three is furthest back on passenger side (of course hte hardest to get at)

Thanks
Dave

Oct 4, 2006 | 02:06 PM

Parts Guy Wyatt

Former Vendor

Joined: Jan 2006

Posts: 3,849

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From: Seattle

did you use motorcraft plugs?

General Specifications Item Specification
Ignition System
Base timing 10° BTDC
Non-adjustable
Firing order 1-4-2-5-3-6
Spark plug gap 1.3-1.4 mm (0.052-0.056 in)
RH original spark plug AGRF22PG
LH original spark plug AGRF22P
New spark plug (either side) AGSF22PP
Lubricant
Silicone Brake Caliper Grease and Dielectric Compound D7AZ-19A331-A (Motorcraft XG-3) or equivalent ESE-M1C171-A

Oct 4, 2006 | 02:54 PM

1081

Elder User

Joined: Mar 2004

Posts: 856

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From: Kansas City, Missouri

check and make sure you have the plug wires on correctly, then when your sure you do, check again.

Oct 4, 2006 | 09:50 PM

maceslin

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Freshman User

Joined: Aug 2003

Posts: 28

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From: Chesapeake, VA

Used Autolite double platinums. Only disconnected one plug at time and have verified good contact on all tips.

Did not use dielectric grease.

Thanks for hte diagram, as feared number three is hte difficult one to get at

Oct 4, 2006 | 09:56 PM

gunsmoke59

New User

Joined: Oct 2006

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i own a 96 F-250 (460 cid) I changed out plugs an did same thing..finally got the right plugs..it makes a diff if you dont use correct plugs

Oct 5, 2006 | 05:07 AM

marragtop

Posting Guru

Joined: May 2002

Posts: 2,450

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From: Baltimore

Did you replace the wires as well? With 125k you should consider it. Also, did you check the gap on the new plugs? Don't trust anything to be 'pre-gapped'. The plugs are easiest to get through the wheel wells.