1999 Firebird (3.8L) Oils

[comiczoner]

I get about 25 mpg here, driving pretty much just on the highway at 60mph. It seems to be higher since I got my oil changed, though, so we'll see.

Also, I guess I should mention that mine is an automatic.

 

[ls1mike]

I used to have a 2001 GTP which lots of modifications. I ran M1 through it. I put 240,000 miles on it with no problems
I had a 98 Bonneville that I put 250,000 on I just ran 10W 30 Castrol in it. Changed it every 3000 miles never had any problems.
Both cars had the 3800.