1995 Geo Prizm 1.8L surging problem that occurs intermittently at various rpm's

The mechanic used a ac delco coil. I re-replaced the coil with a masterpro thinking that the one he put on was bad. The car runs the same with either coil

Do you have any codes on the OCD? This sounds like a problem I had with a transmission sensor. My car would suddenly shift up or down a gear causing it to rev. 1st mechanic I took it to found the code but quoted me over $3000 to replace the transmission. When I looked up the code online and found it was the sensor, I took it to a dealer to have just the sensor replaced. It was less than $300 and fixed the problem.

Well I dont think this is any sort of a transmission problem as there is no difference in how the automatic tranny in this car is performing. Which is good