240 burning oil and fuel

[siemata5]

Hey new here to this forum, but got a couple issues with oil and fuel economy for my 93' 240 ka24de :

1)Gas mileage is horrendous for some reason, not sure if it's an o2 sensor that needs replacing or if it could be an issue with fuel injector(s) or fuel filter.

2) Engine burns oil at a faster rate than normal and significant smoke/emission is noticable after i drive for more than an hour. Just bought my 240 on 9/6/09 and changed oil right after purchasing as i do with any car i buy.

If there's any suggestions/advice it would be greatly appreciated, thanks