File this one away. I recently changed the plugs in my 1985 and gap'd them to 0.025inch like the Haynes manual said. As soon as the engine warmed up, it was a terrible idle and constantly stalled in drive. I went crazy trying to figure this out, when I checked alldata.com. They have a TSB that says: 1) normal gap should be .030; 2) Increase the gap to 0.040-0.45 to improve the idle quality. I reset mine at 0.042 = perfect now. Hope this helps you someday.

John

Submitted by jam@ispwest.com on Mon, 03/14/2005 - 17:33

hi John,

I second Maury's comment, those Haynes "manuals" are a joke. Get the CD Service and Parts manual from Jaguar, around $25.00 at Jag dealers.
But I will definitely keep this spark plug gap info. handy. I've had the "hunting idle" problem but it turned out to be a loose vacuum hose at the Charcoal Canister. I like the Splitfire plugs myself; The engine ran great with them, and as soon as I changed to the Bosch Platinum it got
lazy. I've heard the Splitfire quality went downhill, but at least my plugs were great. Going to try them again.

JAM