No. There are not "spark plugs" on turbofan engines. There are ignitors, which help to ignite the fuel during start, but unlike spark plugs, ignitors do not run constantly.
A fouled spark plug will make you lose horsepower if the plug is not producing a good spark. The other thing a fouled plug can do is if it is not firing right the fuel that gets into the cylinder...
If you are talking about actually coming out of the block, it may be that you did not use the metal gasket that some use or you did not tighten it enough when installing. I believe these are TSB's...