how many miles?
plugs?
Air filter?
Clean the TB.
is the clutch worn?

My mileage is at the worst high 20's in town - 28/29
on the highway - 30 to 33 mpg

does it use oil - could plug the cat or foul the o2's
lots to check into

 

Yes, it is using oil... about 3 quarts per 3000 miles.
About 80,000 miles on the ticker.
The clutch is not slipping.

Would there be a pre-cat on it? How many 02 sensors would it have?