The 3800 series of GM engines have long been a pain in the butt to me!
I have recently done the mod on one of these, an 02 LeSabre. First tank, he went to 66 mpg's, and has dropped to only 30. On first post-mod examination, I found the MAP sensor literally falling apart. This was replaced, with almost no change in mileage.
What of this class of engine have you done, and what were your results?
Did you find areas of concern?
If so, share your findings for the rest of us!
Ron
