[muddog321]

See many posts on 97 failing ignition switch which when you look it up is the connector and wiring harness in the column. In fact I have seen a tech article on many GMs in common with this and often worse when a blinker on as voltage drops to 10v at the connector so engine stalls as PCM sees incorrect voltage. Blazers hate lower than 12 volts and as an alternaor fails the gages go screwy and start swinging all over. Of couse it could be many other things in the fuel, sensor, electrical system based on age, but sorry, the ign switch is the common weak link on 97 to rule it out.