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.
What gives?

 

My brothers 1994 4cyl acted similar to what you discribe, it was his coil pack.

He never tried a code reading, so I don't know what they would have looked like.

Good luck.

 

Sounds electrical to me. Only thing I can offer is to check the alt and batt. Then make sure all the grounds are clean.

Rich