gas mileage droped 100 miles per tank full and lost power on 1995 Buick Riviera

I noticed some hesitation at first when maintaining a steady speed, then I noticed it was all most jerking at steady speed.now I changed the spark plugs,no help,then I changed air filter, no help I took it to a muffler shop and had a new cadeletic converter installed (no help)but what ever it is it's in the fuel to air mix or the super charger it self.
#1.Is the super charger hard to change?
#2. can I get one?
#3.how much are they?
#4.or am I way off on my diagnosis

Asked by for the 1995 Buick Riviera
you are way off. go back to basics. have the fuel pressure checked to see if you may have a leaking fuel pressure regulator that would drastically effect your mileage. could be that simple.

Roy
Hi>, The problem(s) you've mentioned "could" be attributed to the fuel/gas you're
using. Some of our gas stations in the NE U.S. have "problems" with trying
to keep water/condensation from accumulating in their underground tanks.
They don't filter out water from the gas before you pump it in your tank....so a
higher than average moisture content (water in gas) will cause the same
situation. Check with other drivers at that station. - callhow
I have had a service station for many years in the NE and there are several filters for this. granted, it will not be 100% effective but does get most of the contaminants. If this was the problem, then a lot more people would be effected and the service station would be bombed with complaints about this issue. I still think a back to basic approach is where you need to start.

Roy
2 more answers
Hi>, The problem(s) you've mentioned "could" be attributed to the fuel/gas you're
using. Some of our gas stations in the NE U.S. have "problems" with trying
to keep water/condensation from accumulating in their underground tanks.
They don't filter out water from the gas before you pump it in your tank....so a
higher than average moisture content (water in gas) will cause the same
situation. Check with other drivers at that station. - callhow
Whens the last time U changed the fuel filter?