This one has me stumped and has put me to the side of the road a couple of times. I have an 1989 XL with an 8v92, DDEC II. Once in a while, the SEL, CEL, and Cruise control lights come on while driving down the road. The bus loses power, but the lights go out if you lift out of the throttle, and the power resumes like nothing happened. No smoke when this happens. This used to happen occasionally, and only when the cruise was on. Now it happens with cruise or normal driving. Mostly on the highway, and seems to be happening more often. It also seems to happen after 4-5 hours of driving in hot weather (mid 90's). The other day, it kept happening when I lifted out of the throttle and it would only run at about 15 mph. Pulled over, wiggled the wires after a restart (no change), and it ran fine for another hour until the next stop.

It does not throw a code. I have done the wiggle test and got nothing, voltages at the ECM are good. No bent pins, and I used some contact cleaner on the ECM plugs/terminals with no change. I've tightened all connections on the front and back junction panels, replaced all the relays in the ignition and engine run circuits, and replaced the rear start switch. Figured I couldn't go wrong with those, seeing as it is 21 years old. Engine runs great otherwise. Any one ever have this happen to them and know of the fix?

Jon - I know you don't like chasing intermittent problems, but I have a feeling that this one is going to leave me by the side of the road and require a tow..... I'd like to prevent it if possible.
Thanks
Steve