I posted this question in another thread and didnt get a answer, Im hoping someone who frequents this thread may have the answer.
A friend of mine recently purchased a 93 f150 with a straight 6 and over 200k miles. Overall the truck runs well... but for some reason he is having alot of problems with his spark plugs. He is having to replace them every couple thousand miles because (according to him) the plugs keep backing out. After driving the truck for a while he can literally reach in and remove the plugs with his hands... no tools required.

What can he do to fix this problem?

Thanks!

 

Tourque them correctly the first time. Don't use too much anti sieze.