: 1999 deville North** lost mileage

05-29-06, 06:53 PM
went from 28-29mpg @ 68 mph, hwy driving to

24, 25. Engine runs great. Also, temp in summer reaches as high as 215 degrees is that ok?

05-29-06, 08:03 PM
215 is normal. Check the FPR for the milage drop. See the Tech Tips section for a "How To" (very easy).

05-29-06, 08:28 PM
I've never had over 25ish mpg highway...