Quick, immediately google "timing chain tensioners" on your engine. If you do not know that the tensioners in your engine have been replaced with the newest updated tensioners. Stop Running The Car right NOW!!!! The only warning you get before catastrophic timing chain failure is (sometimes) a ticking sound. Get this checked out by someone that knows the car post haste. If could always be something else,but this is a known expen$ive problems with V8s of your era.
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Jesse Bogan
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'93 XJ6
'89 XJS coupe V12
'87 Audi Turbo Quattro Wagon
'67 Chevy Corvair coupe
Uh ohh 64 Chrysler newport hardtop wagon