Ok, first a description of the problem.

Took car to the track last week, trapped 110-111 most of the day, felt good until the last pass. On the last pass of the day, the car falls flat on its face in every gear, the exhaust tone has an off sound, and the trap speed fell by 6 mph to 104. On the return road the car is running rough under load, in gear. Grabbed my timeslip and decided it was time to limp home. Checked the oil (pressure looked fine), took a look around at connections and so forth under the hood, then decided to limp home. Valvetrain was and is dead silent, no unusual noises or anything of the sort. On the ride home, the car had an awful driveline vibration at speed, the tranny and motor seemed to shake in the mounts. Exhaust tone had a very 'off' and flat sound. Motor sputtered and hesitated under acceleration.
However, there is no exhaust smoke, oil pressure still looks fine after the 75 mile ride home, and valvetrain still sounds completely normal and quiet. The car starts and idles normally, but hesitates and seems to miss when revved, under load or in neutral. PCM (I have an OBD1 unit) has no codes at all.

I have taken a look at the car...

I checked the spark plug wires and none appear to be burnt, but I am going to check them again more thoroughly. I replaced an ignition control module that was cracked last time the car was apart. Symptoms still persist.
Is there any better way I can test the ICM/coil/wires more thoroughly before I narrow the diagnosis down to a fubared opti?

Anyone had an experience similar to this? If so, what was the culprit?
Thanks in advance.

 

One other thing. I completed a cam and valvetrain swap less than 300 miles ago, car made the dyno numbers in the sig less than a month ago, obviously everything was working well at that time. Original vented opti has 104k miles on it.

 

Check the plugs.

 

Ok, if my opti was the culprit, it would be a random misfire, correct? And if the plugs/wires were the problem, it would be a misfire on just 1 or 2 affected cylinders, right? Correct me if I am wrong...

 

The opti can give ya a dead miss on any and all cyls or a sometimes miss,same with plugs and wire's.

Pull the plugs and check them.