4.2l V6 Code Confusion
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4.2l V6 Code Confusion
I have a 2002 F150 2WD w/4.2l V6 w186k miles that is confusing me with codes,I do have a slight Stumble that is felt on acceleration but a smooth idle with no obvious misfire at idle.
Initial code w/SES light on was 302 [#2 misfire] and 316 [misfire on startup]
I ran two bottles of Techron through over the next week.
I replaced plugs [#2 plug was noticeably blacker than others] and switched wires to eliminate wires and plugs and cleared codes,result was same codes[302 and 316] with SES light coming on in 2 blocks.
I cleared codes again and I traded the #2 wire with the #5 wire at the coil hoping to see my misfire go to #5 telling me the problem was the coil pack.
Result was 10 miles with no SES and a 306 [#6 misfire] and 171 [left bank lean]
I cleared codes again and restarted engine and got a repeat of the 306 and a 174? [right bank lean] w/no SES
I cleared codes again and then replaced the wires at the coil pack to their original position
Result was code 302 and 316 again [no lean condition] and SES light two blocks later.
Anyone point me in a direction? The fact that the misfire moved [albeit to the "wrong" cylinder] leads me toward the coil pack and away from fuel issues but I am open to suggestion Thanks
Initial code w/SES light on was 302 [#2 misfire] and 316 [misfire on startup]
I ran two bottles of Techron through over the next week.
I replaced plugs [#2 plug was noticeably blacker than others] and switched wires to eliminate wires and plugs and cleared codes,result was same codes[302 and 316] with SES light coming on in 2 blocks.
I cleared codes again and I traded the #2 wire with the #5 wire at the coil hoping to see my misfire go to #5 telling me the problem was the coil pack.
Result was 10 miles with no SES and a 306 [#6 misfire] and 171 [left bank lean]
I cleared codes again and restarted engine and got a repeat of the 306 and a 174? [right bank lean] w/no SES
I cleared codes again and then replaced the wires at the coil pack to their original position
Result was code 302 and 316 again [no lean condition] and SES light two blocks later.
Anyone point me in a direction? The fact that the misfire moved [albeit to the "wrong" cylinder] leads me toward the coil pack and away from fuel issues but I am open to suggestion Thanks
Last edited by wrooper; Dec 22, 2011 at 01:31 PM. Reason: addition
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A little more searching and I found a poster that listed the wire order at the coil pack is not a mirror of the firing order as I believed. So at the coil pack the wire opposite the #2 wire is in fact the #6 wire not the #5. This tells me the coil pack IS the culprit as switching the wires at the coil pack changed my 302 to a 306
Anyone confirm this for me?????
Anyone confirm this for me?????
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For the 4.2 L - V6 engine coil----3---4
pack---2---6
plug----1---5
Here's what I found doing a Google search on Ford 4.2 coil fire order. Of course, I also saw one answer where they had the 5 and 6 reversed. I think you proved it correctly when the misfire went to cylinder 6 and back to 2 when you switched those wires.
pack---2---6
plug----1---5
Here's what I found doing a Google search on Ford 4.2 coil fire order. Of course, I also saw one answer where they had the 5 and 6 reversed. I think you proved it correctly when the misfire went to cylinder 6 and back to 2 when you switched those wires.
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Update:FIXED
just an update,new coil pack fixed the codes and running smooth now.
I have seen many posts [not necessarily here] that claim that because the coil pack fires in pairs that a single cylinder misfire is not coil related,my experience is otherwise,
Also,switching wires at the coil pack IS an effective way to determine if coil is the problem ie if it wires or plugs or injectors the misfire will not change cylinders [be sure to only switch wire to the coil post on the opposite side of the coil]
hope this helps someone else
I have seen many posts [not necessarily here] that claim that because the coil pack fires in pairs that a single cylinder misfire is not coil related,my experience is otherwise,
Also,switching wires at the coil pack IS an effective way to determine if coil is the problem ie if it wires or plugs or injectors the misfire will not change cylinders [be sure to only switch wire to the coil post on the opposite side of the coil]
hope this helps someone else
