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Running rough after plug change

tmfulton

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I put autolite spark plugs in my 1996 explorer v8, gapped according to specs and now it runs rough. Should I use only Motorcraft plugs?
 



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Autolite is the same as Motorcraft. I'd check your connections and be sure you have the correct firing order.
 






They used to be the same, but not anymore. Autolites are now made in Mexico. The electrodes look to be poorly made too, with a 'rounded over' appearance rather than sharp precise bends.
Out of the last 14 new Autolite plugs I've bought, 2 were bad. One was bad right out of the box, and the other went bad after just a few thousand miles.

It was trial and error in finding the bad plugs; I'd change one bank and test drive to see if the miss went away. Funny thing is, the last bad plug ran well during driving (after it warmed up), but misfired at idle. It was very slightly damp when I pulled it, so it was suspect immediately.

Needless to say, I've bought my last Autolite plug.:thumbdwn:
 






Make sure that all the wires are seated properly and that none of them were damanged when the plugs were changed. Also, make sure you didn't knock a vacuum line loose.
 






I've had the same problem with my 99 XLT SOHC for a while now after changing to Autolites APP103. I also changed the wires, but I'm pretty sure its due to the plugs. It has the "vibrating" idle everyone talks about on this forum. Next time I'm going back to Motorcraft and seeing if that solves the issue.
 






It's possible you cracked an insulator when installing the new plug...especially if you didn't use a special spark plug socket that protects that from happening.
 






Autolite Plug problems

Thanks for the info. I thougt maybe I damaged one of the plug wires (they have 101,000 miles) so I replaced them. The truck idled fine (better) but, under load misfired. It did run a little smoother. it got late so I benched for the night. I'm putting in some Motorcraft plugs right after this note, I'll let you know how it goes...
 






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