Pontiac Repair: 2000 pontiac bonneville ssei eractic idle, fuel pressure regulator, vacuum leaks

Question
When I start up my 2000 Pontiac Bonneville SSEI it idles real rough and erractic between 1500 and 500 rpms every second and then stalls out. It will restart but does same thing again. Could be the problem be the fuel pump or the computer or what? Thanks

Answer
Hi Mike:

well this can be a bunch of issues. My first though is a vacuum leak. how does it run hot? erratic idle or a higher than normal idle? if so I'd lean towards a vacuum leak. You could have a fuel pressure regulator that's leaking gas into the vacum line for the regulator and when you start the car it's running to rich and dies out. it could be a carbon build up issue on the intake valves and on a cold start the carbon is absorbing the fuel and the engine is running to lean and dies out.. That can be fixed with a product called top engine cleaner that is sold at gm dealers.  You could have a fuel filter that is plugged and the engine is being starved for fuel on a cold start... But my first guess is where I would look. The gasket between the super chager and the intake manifolds tend to go bad on these especially if it has a lot of miles on it.. Also ther is a vacuum line that is right under the nose of the super charger that cracks and causes vacuum leaks as well. Good luck :)