The engine light stays aluminated with a PO128 code. The engine starts, the rpms go way up momentarily, then dies if you leave your foot off the gas pedal. Not every time, but most of the time. Could this symptom be related to the PO128 code? The coolant level is fine, so am thinking the thermostat may be stuck open since the temperature gauge never goes over the 1/4 mark. Not my car so don't know where the temp. gauge should be when the engine is warmed up. This is a 2004 Grand Prix GT 3800 Series 3. This was the only code that came up. Also, is there a separate "Service Engine Soon" light on these cars, besides the engine light?
By looking at it, looks like maybe the thermostat is sitting at the end of the upper radiator hose, is this right?
