10W-30 is a pretty standard oil but it depends on where you live and what type of climate/temperature10W-40.
An engine compression test on a 99 Grand Prix GTP can cost $180
Yes
3.8 liter
Grand Touring Prototype
Yes
Yes, both cars had the exact same 3.8 series II engine.
With a scan tool.
how to reset fuel pump,on Pontiac grand prix GTP
The GTP is supercharged and the the GT is just the 3800 engine without a supercharger
on the passenger side of engine by the wheel well
Grand Touring Package
in my 97 Grand Prix GTP I have gotten 32mpg on the highway and the most miles I have had on a tank was 470 miles!!