HELP! 99 Volvo S80 Big problems. Fuel leak, mystery, etc

We have a 1999 Volvo S80 that has had a long and traumatic life. Recently, we noticed it idling low (under 1000 RPMs), idling rough at stops and lights, (felt it was gonna die while stopped), and running through gas VERY quickly. Also, there was a noticeable smell of gasoline, which was VERY strong while in our garage. So, we took it in to the mechanic, after researching some possibilities on line. We told him we suspected a fuel leak. Seven hundred dollars later, he returns the car, saying he had replaced the Air Flow Meter and one of the 02 sensors. When we got the car back, the warning lights (check engine and emissions) were out, like it was OK. Car was fine–for 5 days. That saturday, we took it out, and lo and behold, the rough idle came back, accompanied by the smell of gas, and both warning lights came back on. We took it back to the mechanic, who got defensive, claimed we were accusing him of fraud, but looked at it anyway. A day later, mechanic says there is nothing wrong with the car: they let it run, they drove it, and there was no rough idle, no smell, no nothing. We picked it up from the garage on Wednesday. It drove just fine, and aside from the low rpm idle, all the problems were not present, AND the warning lights on the dash were not lit up. This Saturday, we were out on errands, and it happened just as it did last weekend–rough idle comes back, gas smell is back, AND we think it is still running through gas more quickly than normal.



Please help, as our highly-reccomended mechanic has made it clear he can’t and/or won’t.



Car is popping ODBII Codes:

p0300

p1171

Pending:

p1132

p0171



Thanks.

check fuel intake system sound like your gas is going out the tale pipe unburned