My '02 Z-28 has 7,100 miles. I wanted, (really wanted), to run my club's last autocross today. On the way to the event, I thought I felt a miss, but it went away as fast as it came. During my first run the miss returned, and the light came on. The light went out, and I took my second run. The light stayed on so I left the event. The light will flash for a while, (I counted 10 flashes, 25 flashes, 32 flashes, and too many flashes to count), then stay on for a while. Then it flashes again. It feels like a dead miss. Do I need to take it to a dealer, or can anyone scan it? Have any of you had this issue before?

Had a similar issue in my 99 C5 - turned out to be a chipped spark plug insulator. Does it miss at idle? Might look underhood in the dark for arcing.

It does miss at idle. And now that you mention it, it felt like a plug or wire. I'll check it in a little bit. Thanks.

I don't see any arcing. It smells a little rich as well. I'll check it again when it's completely dark.

Sounds kind of familiar to what happened to my Jeep, the code came back as a misfire on #2. I tested the coil, un-plugged injectors, pulled the valve cover, did a compression test.... it turned out to be a bad plug. It became obvious when the misfire jumped to a different cylinder when I moved the plug. It turns out the resistance didn't match another plug, I forget exactly what it was doing wrong, either open or varied according to my voltmeter. The plugs were only 3 weeks old so I was able to return that one!!!

Remember when it happened to me at RIR when you were instructing shotgun? check the coilpack and spark plug wires!

if it is flashing when it is running it is trying to tell you that the miss is bad enough to damage the cat. So you need to find which plug or plugs are not firing.

If it misses from a cold start, then the misfiring cylinder's exhaust should be cooler than the rest - shoot the exh manifold stubs with a IR thermometer, or a squirt of water. Find the one that's cooler than the rest, reseat or replace that plug wire, or/and the plug. If that doesn't fix it, swap the coil to another cylinder and see if the problem follows it.

I'll get back to it tonight. Worse auto-x showing in years, but there was no way I was going to keep driving it. It was flashing while I was driving, then it would stop for a bit, then flash again. Great idea with the IR gun.