500 efi skipping after coil change
 

Coil was looking a little bad so I decided to change. While I had it off I painted the mounting bracket. Took it to the lake yesterday and fired it up ran great for about 15 seconds then it shut off. Cranked it back up and it spit and sputtered then shut off. Did that a couple times then it started idling right. Tried to come on plane with it and it would get up to 3000 rpm and start skipping. So I put the old coil back on to see if it was the coil. Done the same thing with the original coil. Checked all wiring and plug-ins and everything is good.

Any suggestions would be helpful.

I'd immediately check/try another ignition coil wire. Maybe the wire itself or one of the ends.

That's all I got (although probable) without checking things in person.

I changed spark plugs and that did not help. I will try swapping coil wires. The funny thing is how it first acted with it dying. But now it idled fine. It also back fired when it starts missing.

I'm going to replace the control module on the distributor also this morning and the coil wire.

I was thinking coil wire myself. You can measure the resistance with a multimeter. The higher the resistance is bad, the lower, the better. Someone correct me, but I wanna say its 40-50ohms per foot is normal. But that is 8.5mm accel wires. Heres a good reference.

MSD Ignition 8.5mm Super Conductor (40-50 ohms/ft)
Accel Thundersport (150 ohms/ft)
Taylor 8mm Spiro Pro (350 ohm/ft)
Aurora ignition wire set (400 ohms/ft)
Vitek Performance Cables (their web site does not mention resistance, but John Monnin measured them at about 800 ohms/ft; the label under Vitek's braiding says "Magstar Gold 8mm High Performance S-4 Stainless Steel Mag Wire" - thanks John!; Magstar wires are manufactured by Wiretec)
Wiretec Magstar Gold (800 ohms/ft as measured by John Monnin)
NGK Resistor Spark Plug Wire Set (2600 ohms/ft)
Mitsubishi factory wire sets (3000++ ohms/ft)
Car Quest brand wire sets (3000++ ohms/ft -
Magnecor KV85 (6000++ ohms/ft)

Changed coil wire and distributor module. Still have the same issue.

check the IAC. they are known to go bad.

Would the IAC make it run rough at higher rpm. It idles perfect. When I took it out yesterday. It idles perfect but when you try to come up on plane as it start to set down the rpm's come up between 3,200 and 3,500 is where it starts missing. I can pull back on the throttle to around 2,800 to 3,000 and it will stop. It seems like the load on the motor is what does it.

How does your contacts look on the cap and rotor? I worked on a 454mpi and it idled fine and around 3000 is would start missing. The contacts were heavily corroded on the cap and rotor. Fixed it right up.

You said that you painted the mounting bracket. That bracket is not used for a ground for anything, is it? There have been other instances on here (OSO) where people have painted stuff near the distributor that has caused numerous headaches because they unknowingly eliminated their grounds, with paint.