97 PCM Replacement

I have a 97 Wrangler with a 2.5, Automatic Trans. I have had a problem with #4 cyl missing out. I already did the new plugs, Wires, Cap and rotor. The first dealership said it was misfiring on #4 and it could be a stuck lifter, bad valve, or blow-buy and it could cost $800.00 or more to fix it. The compression is the same on all cylinders so I took it to another shop. The shop said that it was the fuel injector even thought I already swap it out with #3 and it still misses out. So they put in a new one and it still did it. They then said it was a short in the infector wire, nope. Then they opened up the valve cover and said that all the valves and lifters were working fine. They tried the crank sensor and still nothing. Now they said it has to be the computer/PCM that is bad and need replaced. I have called several Dealers and they all say that there is on 3 available in the country and they are all rebuilds costing $557.00. Is this my only choice? I also have a problem sometimes when I would start up the wipers would run for about 5-15 minutes before they would shut off so I would put them on delay until then. This dosen't happen all the time though. Could this be related? Any help or suggestions please.