Engine Performance problem
1987 Oldsmobile Ciera 6 cyl Front Wheel Drive Automatic
I pulled codes from my car using an code reader. The code I got was " rich exhaust indicated (left side dual oxygen modules)" and the other code was " Electronic spark timing (EST) circuit - low voltage detected. Electronic spark control (ESC) - circuit problems. WHAT DOES THAT MEAN? WHAT DO I FIX?