I bought a used 97 SSEi that came from a GM lease program. Could someone let me know where the needle on the boost gage should be operating at. My boost gage needle is always around the negative 10. The needle only moves when I accelerate. As soon as I step off the pedal the needle goes back to negative 10. I was reading the owners manual and the description of the boost gage suggests that the needle is supposed to operate from the zero in the middle of the gage. The car has already had a new water pump and a new transmission installed. Luckily I bought an extended warranty. Also the car keeps stalling all the time. It is getting pretty dangerous when it stalls right in the middle of the freeway. I went to the Pontiac dealer. They said there is a leak in the lower intake. I then brought the car to the garage that my extended warranty mandates it be repaired at. I told them what GM said needs to be repaired. They performed the work. They also advised me they would not do any further repairs for the stalling if the problem continued based on GM'* diagnosis. Well the car still stalls all the time. Brought is back to GM. they advised there is still a leak in the lower intake and they won't repair it. They advised I have to have the warranty place redo the repair. Really screwed now. I haven't gone back to the warranty place. I am not sure who to believe. I can't afford to keep having this car diagnosed. I have replaced the fuel filter, fuel pressure regulator and air filter myself. No improvement. Also computer is throwing a Lean code for system adaptive fuel. I am using lots of octane boost. Not helping. Any information any one might have would be greatly appreciated.

I have a 95 SSEi. So I should have the series 1 and you the series 2 but that shouldn't make much difference. My boost gauge also idles at -10 but as soon as any pedal is applied it starts to rise. -10 just means that the supercharger isn't forcing enough air in to equalize the internal pressure vs. outside air pressure. This is normal. My buddies GTP only shows you 0 to 10 psi so you have to stomp on it a little to register. Chances are if you bring it up to say 4000 rpm your needle should have something closer to zero continueously register.

The supercharger is always running and pumping in air but once it hits zero it is then forcing more air in than it could possibly get on its own. Above zero is where the power starts to come out more.

As far as the lower intake, I have blown 2 of them. I had severe stumbleing acceleration problems as well as problems idleing smooth. Once it was replaced everything went back to normal. But if they say it still leaks and it is under warrentee, take it back and have them fix it, again.

What RPM does your car idle at and does it idle smooth?

I have also had similar troubles on non - */C cars I owned in the past that turned out to be vacum line problems. Maybe that is somewhere else to check into?

Thanks for the information on the boost gage needle. The car idles at around 750 rpms. That boost needle also moves erratically up and down during idle. But only up and down near the -10. The idle speed seems slow to me and sounds slow compared to my last car which was a SHO.
My SHO was a mechanical nightmare, but a lot of fun to drive. I'll check the vacuum wires again. I found some that were not fitting too tight at the ends near the throttle body and the actuator for the supercharger.

Mine idles aroung 900+ rpm and I also have the slight flux of the needle around -10. Looks like that atleast is nothing to worry about.