Hello all,

A few months ago, I upgraded the ignition system of my 97 4.6l 4x4 crew with accel coil and plug wires. I didn't change out the spark plugs as I had Autolite APP104 installed only a few months earlier. I didn't get the bump in mpg that I was hoping for. However, last night I was reading some threads that suggest increasing the gap on plugs when upgrading the ignition system.

Does anybody know what the gap should be with the more powerful ignition system? Am I running the right plugs or should they be changed out also? What impact will increasing the gap or plugs have on my mpg and performance?

Thanks for any help.