Hi Scotty,
I started and took my 06 Grand Marquis out today. It had been sitting since 12/29 with the exception of starting it once. I noticed after driving it about 10 mins. It started to sputter and idling rough while at lights. The check engine started flashing and I took it to Oreillys and had the OBD scanner hooked up and read po304 cylinder 4 misfire. A few have said a bad coil. I'm not sure? Thanks, Joe
It was a shorted out coil on cylinder #4.
@joeo That would certainly do it. Thanks for letting us know how it turned out!
One thing I failed to mention. When I started my car, the wipers weren't working. I've had this happen before in the winter due to a bunch of ice building up underneath windshield where the tray to collect leaves and debris lies. I went to the self serve car wash and doused the area with the sprayer. The wipers started working, but I wonder if I may have got one of the coils wet in the process.
@joeo - Check them to see if any are damp. Also, a simple test for a bad coil is to swap it with another cylinder and see if the misfire travels with the coil.
Thanks