Hello everyone,
I have owned my 2004 Grand Prix GT1 for just over 10 years and love driving it. The only mods are lowering springs and a tune.
Just over a year ago it started acting weird, it's like the throttle has a mind of it's own and it comes and goes. The throttle acts like it closes and opens back up after giving it a lot more throttle, then it shuts down again. After getting up to say over 40 mph it will usually return to normal. Turning it off and then restarting makes it go away, sometimes for a while, and sometimes just for a short while. I've replaced the throttle body control unit and it still does it. I've verified that it is the throttle opening and closing by running my scanner with live data and watched the tps reading change when it started acting up.
Steve