Car was running just fine all week then we got a lot of rain on Saturday and I went to start it up and it was misfiring on Cylinder 6 (P0306). Left the car alone until Monday and now when I drive it runs fine until I give it enough throttle then it starts missing until I let off the gas. I’m guessing coil pack or wires are the issue but I’m not sure as I’ve never encountered this type of issue before.

Monday night I took the wires off the coil packs and found a little rust on the connection for cylinder 1. Cleaned all connections and still am missing under load.

 

This miss fire could be almost anything with the ignition or fuel system.
I am not a throw parts at it kind of guy. But if you are due for plugs, wires, fuel and air filters it may be a good times to do that . Keep your old ones until you have this sorted. If it misses all the time under load a tech with a scope can narrow down if its fuel or spark. You may need a good scan tool from that point on to data log what is happening when you feel the miss. Spark is generally easier to find then fuel issues. Since these cars are getting older you could try wiggling some areas of the harness to see if you get a reaction.

The problem with throwing parts at it is there is a chance you could install a bad parts now you have 2 issues and that can be a nightmare for a tech. In the shop when one of the guys yells Grenade we all know what that means. Someone dropped a parts grenade in the engine bay now we have an issue. Even at the dealer many techs have there known good parts they keep cause they know there is a chance the new ones are defective.

 

Thanks for the insight! I just replaced the spark plugs last year and changed the air filter and cleaned the MAF in 2020 but the wires and coil packs are all original from 1997. I am going to try wires first and see if it changes anything, If not I’ll keep going one thing at a time until I can narrow it down.