No check engine light before they were unplugged. Only problem was the stutter/stumble at low RPMs.

 

FWIW I chased a "stumble under load". while it was VERY frustrating to find why...it turned out to be #6 plug boot arcing against the boot heat shield. Could not see from up top, even in dark misting with a water bottle.

was under car with engine running and saw the arc from underneath

point is you really need to look at all angles on EVERY plug. Use dialectic grease inside plug boots

 

Heck it only takes a minute to monitor fuel pressure...

 

Injuneer, I've had the headers on the car for about four years with no problem. Then a few months ago the noise from the exhaust leak started. I found a bolt had come out. I replaced it but the headers still leak. What are the chances the header flange has warpped?

To all, I've gotten new gaskets and wires to put on the car. I'll report after I get them on if the wires helped.

 

I had the same problem right after I installed my mac mid length headers. Plug wires were arcing quite a light show at night. Ended up going with Taylor 8mm plug wires and a OVC set up. Problem was solved.

Solving the problem wasnt that easy, I automatically assumed it was the OEM opti and with a 130k on the car, went ahead and replaced it along with the coil. Still had the problem. Later when popping the hood outside in the dark I saw the light show from the plug wires. Actually was looking at something else and then saw the arching.

Good luck.