what does code 27 48 mean?

 

Well -- in the old ODB 1 codes ----

code 27 --> quad-driver module (computer) 2nd gear circuit

code 48 --> misfire diagnosis

 

Did you have any trouble with it idling high? I'm having that problem intermittently, along with high idle.

 

High idle, intermittant or otherwise, is likely to be caused either a bad Throttle Position Sensor (TPS), or a vacuum leak somewhere in the myriad of hoses under the hood. Having a Hayes/Chiltons/Mitchell shop manual would be a really good idea to help you trace the hoses ....