Recently did MSD opti, Taylor Thundervolt 8.2 wires, NGK Iridium IX plugs. Also, Pacesetter mid length headers and a Cloyes timing set.
Ran well for a couple of months but now starts to miss after it is warmed up. The coil is a 14-15 year old MSD unit. Do you think it is the coil? Any suggestions on what coil to use?

 

When does it misfire - at idle, under moderate load, under full throttle, all of the above?

Have you checked for plug wires burnt by the headers? Did you Loc-Tite the rotor screws before you installed the MSD Opti? Have you had the ICM tested, while heating it up?

 

Misfires under all above conditions. Unfortunately I had it together before I heard about the rotor screws possibly loosening... But, I drove it yesterday evening and lost my power steering. When I looked I saw the serpentine belt was wet. Upon closer inspection, I saw coolant on part of the water pump (also new). Apparently something is leaking and getting something wet... I am thinking this was just not put back together tight so my mechanic is picking it up from the Piggly Wiggly parking lot soon....
I HOPE this is all that is wrong. I read some other misfire issues on the board here and they are all ugly.
By the way, anyone here considering a MSD Opti, I give it a thumbs up. When it was first installed I could not believe the difference it made in across the board performance. And when The oil seal behind it leaked and ruined it (60 days old), MSD replaced it free of charge under warranty even though I told them that there product did not fail. Wow. Can't say good things about a lot of companies and services right now, but MSD is great in my book.

 

Good luck with this.

You know, you're clearly in the minority when it comes to endorsing the MSD distributor...almost everyone else swears at it as opposed to swearing for it....

 

Our your headers coated? They can ruin o2s over time when the coating burns off.

 

Actually, the volatiles burn off when they're new....often ruining the O2's. I haven't heard of this being a long term issue....

 

I waited two weeks and replaced mine. Probably right that it would ruin them quick if it did.