I've been told that i need a new timer, do I? and misfire in 1 that isn't constant, what do you think/

I have a 2000 Plymouth Neon 3 speed Automatic 2.0 whatever, and the fan almost never stops, when it does, it's for 10 seconds and starts up again. The air condition is great, but it sweats like crazy, I can see puddles accumulate under the car when it sits. I just changed the upper radiator hose and the car's running nice, like it got more power, the old hose was almost twice the size of the new one, the old one finally burst. Now there's a slight hissing out of the engine over by the belts where the hose busted. The Timing belt busted about 7 months ago and the mechanic says that one of the piston rings won't work right, nut that the car'll run. The check engine lights on and I checked it, misfire on one. It goes away and comes back sporadically. I've tried high octane gas, low ocatne, 5-30, 10-40 and 20-50 oil, synthetic, blend and regular, injector cleaners, but nothing keeps it from coming back. The longest the light stayed off was when I changed the plugs.
I've been told that i need a new timer, do I? and misfire in 1 that isn't constant, what do you think/
Use a ohm meter to check your sparkplug wire, or us a spark tester between the wire and plug. Sounds like bad wire or coil.