Here's the problem.. I have a 98 tj 4.0 that I've been battling with a hesitation above 2k mostly noticeable in third gear. A year ago threw a code #1 cyl misfire. 158k miles so I started inquiring what could cause this. I quickly found out that only a thousand things could do this. Here we go.. I've replaced exhaust front to rear with magnaflow high flow cat and muff. New 02 sensors, clockspring, all sensors on throttle body, and fuel pump. Bit the bullet and pulled the head. Aha.. burnt valve#1 cyl. Replaced the head with atk from 4wparts. Upon setting engine to TDC noticed that at TDC Rotor on distributor was about 8 deg from directly at #1 on cap. Could this b my problem with hesitation. Can this advance make it run rich to the point of burning valves?