MMO application
 

I bought a 1993 RX7 that had been sitting for 12 years. All original with 18000 miles I am changing all the fluids and filters and was told to put mmo in the plugs, let sit then hand turn. My question is do I put it in all 4 plugs or just the leading or trailing. Thank you Chuck

Just in both leading holes should work best since they're lowest on the housings. I would probably check your fuel tank and consider getting the injectors cleaned. 12 years can do some serious stuff to the fuel system. Best of luck!