Hi again,

Thanks for all the comments. Connecting the disconnected air intake duct seems to solve the excessive fuel consumption problem. I couldn't imagine that a disconnected intake duct would do this much. To be honest I still don't know if the problem was this but it seems that it is solved for now. I'll monitor the consumption thouroughly during the week and if it still normal then, I'll know for sure that it caused the increased fuel consuption.
Ihsan 854 nonturbo

ONe more thing to check. We had big decrease in MPG and as I was looking over after a short drive felt much heat coming off brakes (rotors).

I've heard of several folks having brake problems, and if yours are not releasing properly perhaps they are the problem. Drive around a little and put your hands near wheels. If you feel lots of heat then time for brake job!

Are any lights on? Check engine etc...

A search archives to get info on checking your flame trap!

Other tune-ups - Air, gas, oil filters, distributer & rotor.

Anyleak in gas tank or line?

I'd think that with mileage like that you'ld see a check engine light with codes and that it'd be running very poorly.
The cause isn't like bad plugs but I'd start by checking your fuel pressure (done with a test guage from the valve on the fuel rail) and looking closely at the fuel pressure regulator on the fuel rails underside. After running the engine, remove the vacuum hose to it and see if gas is dripping from it into the vacuum hose (shouldn't) as that would cause your problem.
Also check other vacuum hoses for cracks, splits. If non-turbo, remove the plastic cover over the throttle base as vacuum hoses sometimes split at the vacuum tree there.
If you replace spark plugs, OEM Volvo plugs are your best bet but they aren't likely to be the cause of your problems unless they've never been changed and causing a miss (would set a fault code then however).

Did you check the throttle body? If it's very dirty (which may be the case since the previous owner rode it hard), then it may need to be cleaned? I would also check to see if there are any codes in the ECU computer. Go to the following website: http://au.geocities.com/ozbrick850/computercodesvolvo.html It will tell you how to read the codes, if any. If there are no codes, and the throttle body is not dirty, I would check the air filter, as well as the gas filter. If the gas filter is dirty, that will lower your gas mileage. The fule cleaner is probably something you should do for several gas refills to make sure the fuel injectors get cleaned.

Delgado