We own a 97 Aerostar with the 3.0 ltr. engine. My wife noticed the check engine light on the other day. Right away I pulled the battery lead off, which was a mistake. It put the light out but I noticed that the van was running rough. My wife said that it was worse now. Maybe because the van was trying to learn the MAP over again.
Took the van to a Sunoco station today on Memorial Day and the guy stuck a OBD-II scanner on it and told my cylinder #2 has a misfire. So, I picked up new Motorcraft spark plug wires and Bosch Platinum 4 plugs. Found out #2 was on the passengers side so I went right to it and the plug looked beautiful. I changed plugs and wires 1-3 and there was no difference. So I had dinner and was thinking, hey maybe because the scanner has to know so many vehicles it got #2 and #5 mixed up. Sure enough #5 was black, Changed the plug, no change. Changed the wire and bingo!!
All I have left is fu$%! plug #6 which I will do on Thursday. It looks like the cause of the failure could just be that the dielectric grease was old enough that a little moisture got in and the spring clip that clamps onto the plug had corrosion causing arcing inside the boot. I changed to Autolite Platinums at 60K and left the original wires. Oh well, live and learn, maybe. It has been a great van for us, we both love it. Although, Ford engineering could have made the access panel to the rear of engine a little wider I really don't think it would compromise the strength of the front end that much. Am I wrong???? I could take a plasma cutter to it and then make my own cover panel. HHmmmm. Well it's not like I've had to go in there to much so far after owning for 27K but it sure is a pain. Thinking of ordering a OBD-II scanner from http://www.scantool.net/elmscan_pwm.htm Seems like a $100 well spent.