I have a 93 automatic rx7. It will start up and run fine .until normal temp
they it start to backfire and die the coolant level is low and the pulg are wet .
my engine has about 3500 mi no it and compression is great said mazda how can i check the water seals

 

1. Coolant pressure test
2. Hydrocarbon test

Any shop should be able to do both for you.

 

Champange bubble test or exhaust sniffer to check for coolant.

But if you say you are seeing wet spark plugs and it's from coolant, the writing is on the wall.