How much does it cost to replace a computer on a 2002 ford escape?

I have replaced my coils, plugs, plug wires...I've replaced it all....but my 2002 escape is still %26quot;missing%26quot; or sputtering - especially in times when it is wet. (rain, melting snow, HIGH humidity) so I was told I might need to replace my computer. Anyone know how much a dealership (roughly) charges for this?How much does it cost to replace a computer on a 2002 ford escape?you might want to check your distribator cap might be cracked and when is is damp outside will cause this problem