[emgzh]

I have an 01 stock motor with 156000 on it my problem is the rear left and right plugs carbon up after two thousand miles the other four are fine, this has been going on for about 15000 miles that i have noticed I have run seafoam thru the intake three times and put it in with the gas and have only been running premium gas in it also tried different brands of plugs still same problem. any help or guidance would be great.

[quinton_T_C]

is the check engine light on... check you o2 sensors have they ever been replaced if they are failing that could cause your car to run rich... take it to advanced auto parts scan it to see if you get a code...

[racin366]

Check the codes, look for vacuum leaks, and you may want to think about replacing the O2 sensors, they're pretty much done after 80-100k miles.