Engine Performance problem
2003 Other Pontiac Models 4 cyl Front Wheel Drive Manual 175000 miles
My 2003 Vibe GT has gone from doing about 500+km before I fill it up (at 1/4 tank left), to now doing between 300-400km before I fill up (at 1/4 tank left). At first I thought it may have been due to a leak in the exhaust but once that was fixed it didn't really change. Is there anything that could cause this much of a decrease? What would be the most worthwhile problem to get fixed that would give the biggest increase, I'm strapped for cash so if you could give me an idea on prices of certain repairs and how effective each might be, that would be great. Thanks!
(also, a fuel system flush hasn't changed the problem either, and cleaning the fuel injectors, as well as using fuel injector cleaner additive to the tank every couple months)
edit: also, this morning when I turned my wipers on they wouldn't turn off. The speed still changes but the lowest it goes is low (intermittent doesn't work either) so I'm driving around on a sunny day with the wipers wiping contantly, any ideas?