Miles per gallon drop..HELP
 

Hello,

I recently bought a 850 Turbo and I was averaging about 21 mpg. My check engine came on about a week ago and since then my mpg dropped down to about 12. And my exhaust smells really rich. Could this be an oxygen sensor problem??? Also when I use my turbo boost, soon after there is a rotten egg smell. A friend told me that's because my fuel is too rich and the cat is doing it's job by burning it off. Is this correct?

Please I need some guidence, I really don't know much about volvo's.

RE: Miles per gallon drop..HELP
 

You could have a bad O2 sensor or a vaccum leak somewhere.You need to pull codes first and see what it says.

RE: Miles per gallon drop..HELP
 

Okay......My codes read 435 & 436. I read somewhere that an O2 sensor can be brought back to life by use a torch to burn out the deposits clogging it and then using carb cleaner to flush it,. Is this true or possible? What's your opinion on this? I have 180k on my car it could be just cloggedcausing it to not read correctly......

RE: Miles per gallon drop..HELP
 

I have never heard of that.I would replace them.I would replace both because most of the time when one goes it wipes the other out at the same time.