1995 850 High fuel consumption

[moacyr]

Good afternoon,

My 1995 Volvo 850 GLT NA is having a very poor gas mileage (something around 15mpg, or less). CEL came on with both P0172 and P0440 codes. I have already read about vaccum leaks, but could not verify it yet because I am trying to fit a harsh bang on reverse. Also it leaves the wall behind where the car is parked really black, due to the exaust. Engine temperature seems fine.

Some other issues:
Lot of oil vapour coming out from dipstick (when idling). Didn't check for the vacuum on the oil filler cap (that PCV sistem test)
Didn't changed the air filter (a bit dirty)

Sollutions attempted:
Changed that fuel return hose just on the top of the engine (next to the oil filler cap). The other one was twisted and i suspected the fuel might not be returning. The new one just twisted again and still fuel consumption kept high

Thanks since then!

[tryingbe]

So, you can't verify vacuum leak because you're also trying fix a transmission issue?

The codes need attention, fix them first.

Running rich will also dilutes the oil with gasoline, gasoline doesn't lube, and pretty sure you'll have a dead engine because of worn out bearings.