i have a 1995 volvo 850 turbo and i just replaced the engine in it, it runs well but the fuel mileage is really bad at about 14 mpg anyone know how i can increase the fuel mileage or what could cause it to be so low?

 

9 times out of 10, a vacuum leak will cause low mileage like this. I would check to make sure all the hoses are still connected and no of them split. If everything looks good there, check and see if the O2 sensors are still in good shape.

 

I too have been getting around 16.5 L/100Km (14.5 MPG). I figured it was how the car was supposed to run cuz that's how i bought it. Im installing a boost gauge on friday, i'll be sure to buy some extra vacuum hose and change all the visible ones
I'll give that a shot, if not, im gonna check the O2 sensors. Is there a way to see if they are in "good shape"?

Thx a lot

 

I'd like to know about how to check O2 sensors as well, as im putting in an order to fcp for later today.