My 94 4.0 has been running odd lately. The rpm surgess from 650 to 450 or less, sometimes leading to a stall. It also gives a lurch [I suspect an engine shutdown] when going down the road, taking the cel out for about 3sec, If the cel doesn't come back on then I now that another 'lurch' is coming. Sometimes I can drive to to work and back without it happening at all, other times it might do it up to 8 times in my 15mi trip.
The KOEO gave me nothing I could make sense of, just a rythmic pulsing.
KOER gave me the codes 99,81,57, in that order. When it went and gave the engine the signal to accelerate it went to one continous beep.
I turned the truck off and the dome lights wouldn't turn off and the electric door locks stopped working. I disconected the battery for 15min, and cured that part of the problem.