I have a problem with my car, sometimes when im accelerating and it gets into high boost and rpm it cuts out and seems like a missfire. I think it is time for me to change my plugs anyway so im going to do that first. Im running stock plugs for a 1994 ssei and what i've done to the car include, Intake with K&N cone, flowmaster muffler, no cat resonator instead, msd ignition, and msd 8.5mm wires. Im thinking of going one degree colder for my plugs, do you think this would be a good idea or should i go stock? Im running ngk right now, does anyone know which ones would be a degree colder? Thanks.

This spring I had a bad plug wire when I got into boost the car would shake and mis fire.
I think 1 degree cooler is fine and will allow you to drop in pulley size for a bit of added boost.

How can i check for a bad wire?

If its been mis firing for a while there will discoloration on the plug wire connection, you can also check the resistance with an ohm meter and compare to the other wires.

Pull the wires off the coil first and have a look, this is where I found evidence of a bad plug wire as the coil post was badly corroded. All I did was clean the post with steel wool and am still using it today. New plug wires though.

Mine did a similar thing with a set of Accel coils. One was bad. It is known that there was a bad batch of MSD'* get out.

Fire up the car at night and watch the engine in the dark. You can find a shorted wire that way.

One heatrange colder might be ok with your mods, but not 2.