What is the thread size on the 1999 3.8 LTZ? I have the plug number. Need to get a compression gauge and want to get the right size thread.

I am finally back to doing some diagnostics. I am pretty sure i have a slipped timing chain. I have been checking voltages and everything else and those all seem to check out great. FUel pressure is also in specs. It has to be the timing chain.

14MM?

Corndog...

Your compression gage will come with any and all thread sizes adapters you need-- yours will be the most common-- if it doesn't- it is a real cheapo gage..I think mine has only two adapters....

Your compression gage will come with any and all thread sizes adapters you need-- yours will be the most common-- if it doesn't- it is a real cheapo gage..I think mine has only two adapters....

It's a cheap one (20 bucks, no adapters). I think the size is right but its so short it wont reach the threads.

Corndog...