The engine runs great under 2000 RPM. Around 2200 RPM the engine surges - it will not run smoothly. I have changed the electronic ignition, rebuilt the carburator, and put a new fuel pump in it. It's a 1989 4.3L with 4 barrel carburator. It runs fine when out of water but under load in the water at 2200 RPM it misses. The problem is not solved. There is a car coil in it. Might this cause a problem? It still surges the same way. Anyone have a solution for this?
