Spark plug mystery

Did you gap them??

Yes, I set the gaps on both sets of plugs according to specs. The old plugs are way overgapped due to electrode wear. The old plugs are in now (still overgapped) and truck is running great... what gives?

gap them wider. may be hotter ignition system. john

"flicks" wrote

You could have twisted a plug wire too much when removing/installing, and broken the internal conductor, and are just lucky that it's making good contact now.

The wire's plug-end terminal might also be loose, and making bad contact with the plug, and again, you "are just lucky that it's making good contact now".

How about using new Champions? I could be that the Bosch plugs aren't as good as you think.

Jeff

flicks opined in news:_1Akc.35047$ snipped-for-privacy@nwrdny01.gnilink.net:

HAh... you find the worst two plugs you could put in a ford.

Champions are just bad, and Bosch Plats dont work in my fords, for some reason... tried in 351, 302 and 2.3... work ok for a day or two, then trhe same problem you are having

Put in a new set of Motorcraft or Autolite...

Hiya all,

Always use NGK in my Granada. The dealer for the Chrysler changed the plugs under warranty, threw out the Champions and fitted NGK to cure a misfire.

Try a slightly bigger gap anyway, possibly up to 50 thou depending on how good your ignition system is, a bigger spark gives a better bang.

pottsy.

Widening the gap away from factory specs fixes the stumble . It looks like some other issue is rearing it ugly head with the smaller gap, something like a lean mixture, bad injectors or something.