07 Roush 427R misfire issue

[AP in PA]

Hello all, I have an issue with my Mustang that has been driving me nuts for awhile now. Read some of the forums here, found them to be helpful, but my exact problem hasn't been covered, that I could see anyway. Best to start at the beginning, car is an 07 Roush 427R 4.6 manual trans, with Roush supercharger, no aftermarket mods, it's as Roush sent it out. Got it in 08 with 14 miles on it. Currently has 24k miles. Garage kept, always premium fuel, maintenance as recommended. No problems ever. Current problem started in the middle of a 90 minute drive to Dr appointment. Developed a stumble, miss, a little one on the drive. By the time we arrived at destination, it was a decent miss. Not horrible, not undriveable, just annoying. Checked in parking lot, nothing obvious. Drove home, not the best thing, but, have driven the ford work trucks way further and longer with worse misfires. Car was barely driveable when we got home. Hooked up code reader, random misfires, misfire cylinders 3,4. Changed coils on designated cylinders. No change. Put all 8 new coils. No change. Mechanic told me change plugs too, that long of a drive probably fouled them out. Changed all 8 plugs, no change. Took injectors out, had them cleaned and tested. Shop said they were a little dirty, tested fine. No change. It sounds like 4 cylinders aren't fireing. Now it says random misfire, lean bank 1 rich bank 2. Have unhooked battery and reconnected a week later, reset codes, no difference. I let it run for 10 minutes and backed it out of garage to clean up, noticed the passenger side exhaust pipe and cat were glowing red. Shut it down and let it cool. Used a laser thermometer on manifolds, cylinders 3,4,5,6 were not even close to temps of 1,2,7,8. I have checked vacuum lines, checked wire connectors, wires, fuel rails with nothing appearing wrong. Checked injector wires with noid light, everything works. Any suggestions would be appreciated. Cleaned mass air, fuel pressure sensor, TPS . I probably have forgotten some of the other items we have checked. Waiting for a local Mustang shop to look at it, they haven't called back yet. Was going to take it to them, but with glowing exhaust, don't want to burn it down or ruin the cats.

 

[Juice]

Time for a compression test.
Glowing cat is indicating a ton of raw fuel.
Where in PA?

 

[Pentalab]

Check both cats. One of em may well be clogged. Cats are before the H crossover. Cylinders count
(front to back) 1-2-3-4 on pass side..... and 5-6-7-8 on drivers side (also front to back).

Cats normally run hot, cruising, like 1200 F..and 1800F at WOT and Roush M90 blower at full boost.
Cats could be either clogged, or internal cat material could have broken off, and gotten lodged downstream, in either the H, or muffler on one side. In the meantime, don't fire up the eng, or drive it.

I'm assuming you have the oem exhaust setup on it...except for the Roush mufflers ? Are the new plugs gapped correctly... at .035" ? (what's used with the M90 + 5 psi boost).

 

[AP in PA]

Thanks for the reply, I thought the exhaust was all Roush. I'll have to check on that. I'd cat(s) are clogged, would pulling the O2 sensors out and starting it confirm the restriction?