I have a 98 TJ Sahara 4.0 with 159,000 miles. Yesterday I noticed when I was stopped at a light at idle I could feel a slight pulsating from the engine. When I gave it the gas and the RPMs increased it went away. I also noticed that if I popped it in neutral that the pulsating stopped also if I pulled away under full throttle it never missed a beat. No skip, no hesitation just haul butt. That afternoon the Check Engine Light came on. I took it to two different auto part stores and both said it had a misfire #1 cylinder code. I bought the Jeep in July and do not know when the last tune up had been done. So I installed a set of Autolite AP 985 gaped at 0.35. The plugs I took out were the same brand and number as the ones I installed and they did not look old or burnt but to be safe I installed the new ones. The distributor cap and wires all look new also but to cover all the bases I cleaned the rotor and cleaned the contact terminals under the distributer cap, disconnected the battery and cleared the CEL. This mourning on the way to work the pulsating at the light is back everything else is the same with the exception of the CEL is not on, at least not yet. Now I know I may need to replace the distributor and wires and maybe the coil, my question is, what else can it be? I love my Jeep but if this gets too deep I may have to let it go. Any help at all will be appreciated greatly.