89 Beretta GT throwing plug

Hey, all. i've got a bit of a problem on my hands. I've got an 89 Beretta GT. it's got a 2.8 multi port FI engine. she's got just under 200,000 miles on her. Now, for some reason that i do not know, this one particular spark plug keeps working it's way out (loosening up). I can tighten it up nice and tight, but it just works it's way out again. The threads in the head is fine, not cross threaded, or torn out. and the plug can be tightened nice and tight, but it just comes back out again. i have to tighten it up every couple of days. does anyone have any idea what may be causing this problem, or how to fix it? Any info on the matter would be greatly appreiciated. Thanks!

The plug may thread in ok and may be tight but is still loose along the threads and works its way out. Only way around this situation is to helicoil the plug hole and reinstall the spark plug. I only hope it is the front plug where it is easily accessible.
Good Luck.

Hey, pcv.........Just what exactly do you mean by 'helicoil the plug hote'???

Hey, pcv.........Just what exactly do you mean by 'helicoil the plug hole'???

Also, i got a tip from a friend. He says i should try pulling that plug out, and putting some locktight on the threads, and putting it back in. I may try doing that. If it will help the plug stay in longer, then it's worth a shot.

so.........thumbs up or down on the locktight........INPUT, ANYONE???

Im sure the threads are damaged, if you keep putting it in and it keeps popping out.. take it to a shop and they can re-tapp (re-thread) the hole.. I wouldnt use Lock tite on my car and im not sure what serious heat will do to it. Take it to someone who can fix it right.
-Jimmy

also buy another plug dont keep using the same one, im sure those threads are damaged and that will ruin the threads on the hole you keep forcing it into.
-Jimmy