Error code 43 "Spark Interface Circuit"

[Chimster]

I have a 1996 Plymouth Voyager with a 2.5L. It has been running very rough; misfiring, rough idling, and stalling. The trouble code I'm getting is 43 which means and interface problem, Ignition Coil Control Circuit problem, or an Ignition Coil One & Two Primary Circuit problem. I have changed the plugs, coil, and wires and still no luck. This is telling me that it must be the interface. Can any body tell me what that means? I think I'm now faced with having to trace the wiring back from the coil but have no idea how to go about it.

UPDATE: I have just changed the downstream O2 sensor but the error code 43 still persists with the misfiring. Does anybody know what else it could be? It's been scanned and scoped but not MOVIE scanned (which may tell me more). I'm told the camshaft sensor could be bad or maybe even the crank sensor (although I doubt that). Worst case senario...ECM.

If anybody has any suggestions please let me know.

Thanks

[yogi_123rd]

Could possibly be cracks in the distributor cap. Were the cap and rotor replaced too? Try pouring a glass of water on the cap while the engine is running and see if you can stall the engine.

[Chimster]

Thanks for the reply.

It's a distributorless system. I have poured water over the coil pack and plugs/wires. No problems there. I'll try it again to be sure.

[Chimster]

UPDATE:

I've changed both O2 sensors. No change in performance (this was after the van was scanned. Iwas advised by a mechanic that it was 'likely an O2 sensor. It's a long story why I changed both!) Next, I just happened to check the plugs/leads by pouring water over them and found a problem. As silly as it sounds, I had a loose plug or at the very least a plug that wasn't seated properly. MAn, I felt pretty dumb after that but I wasn't the only one who overlooked the obvious. I changed all 4 plugs and the thing runs great now. However, I still have the rough idling problem.

I'll have to troubleshoot that next.