I was coming home from school tonight and my ses light came on. I tested it and it came up as............

53 System over voltage - over 17.1 volts OR EGR sensor fault, improper EGR vacuum OR VATS alert.

It is on an 86 4bbl lg4 ta. What's wrong with her?

 

I dunno, but it's not the EGR and it's not VATS. Try testing the incoming voltage with a multimeter, and check to make sure that the ECM power wire isn't crossed somewhere.

 

id check the overvoltage. no way a crossed wire could cuase a surge to 17.1 volts. id think more or less that your voltage regulaotr (built into the alternator) is defective. check with a multimeter.

 

It has been over two weeks and it hasn't done it since. Must have just been a fluke.

Thanks guys