okay, this could get long & complicated, but i'm hoping someone has a simple solution. i just took my 93 240 wagon into the shop (a good mechanic that only works on volvo, porsche and audi's but they do get a little rushed and look over things sometimes)

anyway, i took it in because the other morning i went out to start the car and it would turn but never start. finally after adding some gas because it was low and flooring the gas pedal it started. i kept pressing the gas for a little while until it steadied. as i drove it to the shop i noticed the gas gauge going from 1/2 tank to empty and everywhere in between. also, i've been getting poor gas mileage. anyway, they said it was also running rich and replaced the fuel pressure regulator.

today when i picked up my car, the gas was low so i drove to the gas station to fill it up. on the way there, the engine/idle would surge up and down several times when i would start to slow down and stop and continued until i pressed the gas pedal again (i could press the gas and have my foot on the brake and it was fine). at first it stalled and all the warning lights came on. i finally got to the gas station and filled up the car, thinking this would fix the problem, but it did not. it was still doing it, but not when the car was facing downhill. after driving a few miles around town it got much better and never stalled again, but when i stop it does the surging very lightly for a few seconds and then stops surging. i thought maybe the idle needed to be adjusted, but when i took it back to the mechanic he said the only thing he noticed was the rotors were warped!!?

any ideas?