Cadillac Repair: 86 eldorado rough idle,poor mileage, poor fuel economy, poor mileage

Question
Hello. Recent onset.Engine idles rough,especially when cold and when a/c is on,even when warmed up. Poor fuel economy also. Only code set is for "system problem" PRND123 switch/sensor. Wazup? Thanx!

Answer
You most likely have a faulty PRNDL switch fault which is mounted on top of the transmission where the shifter cable is attached.

This switch needs to be adjusted EXACTLY correct. Please e-mail: onlineautohelp@msn.com for pictures showing how to adjust the switch properly.