My WIFE drives a 1999 windstar with the 3.8 the the service engine symbol pops up intermitently. I noticed a small decrease in fuel milage and at cruise I notice a little chug every now and then. I had it out on a computer but the computer said unable to or incomplete self test. Any clues as to what is going on here. Incidently the o2 sensor just before the cat was bad according to my sensor tester and that was replaced.

Thanks in advance,
Ed

 

if it's unable to complete the test i'd guess power or ground to the ecm, but i don't know much about anything and chryslers even less.

 

Is there anyone that can help?

 

Rad,

I'm not sure about what access software or scanner you are using, but with Auto-Tap, the ignition has to be ON to communicate with the PCM. I don't get the priviledge of working on many Fords, so I'm not familiar with their quriks, but if you can't communicate I'm guessing you most likely have a connection issue with the cable, port, or laptop. Wish I was more help.