94 mercury sable rough idle

1994 mercury sable 3.8 with 115k miles was running well until the coolant hose that runs under the intake manifold caught a hole and started spraying on the distributor. now the car acts like it wants to stall.
I replaced the distributor cap and it runs better but still rough. I also cleaned the iac valve which gets about 12.5 ohms unplugged between the terminals. the plugs and wires look new. is there an easy fix? this occurs mostly when the car is warmed up at idle. is there aliens in the micro processor? no check engine light on at all.:screwy:

I noticed earlier that the coolant gauge moves slightly but yet erratically when the car is warmed up when it sputters. I wonder if it is the head gasket.