Q: My car is lurching when I try to go over 30 mph and if I try to go up hills it tries to stall out on me. If I give it a little gas it's ok but anything over 25 or 30 and it lurches and tries to stall out and some times does stall out. I have changed fuel filter and blown out fuel lines and such. I have checked air filter it's good. I am at a loss. It started doing this suddenly. I want to check my on-board diagnostic fault codes but need a guide on how to do this and what they mean. If any body has any ideas what might be wrong or where I might find a guide for my obd I would appreciate hearing from you. Thanks
A: Volvos have 2 fuel pumps. One under the car and one in the gas tank. When your just cruising around, the main pump can do the job. But when you need to accelerate rapidly or go over 30 then their is too much demand for gas and the main pump can't keep up. You don't get a code for fuel starvation, so reading you DTC's won't help. You can disconnect the hose going to the main fuel pump. Some gas will come out, but then it will stop. Taking your gas cap off sometimes helps. Anyway with the hose disconnected, and no more gas dribbling out. Turn the key to the crank position for just a second. Gas should shoot out of the hose you disconnected from the back of the fuel pump. If it doesn't, then you just confirmed that the "prepump" in the gas tank is not working.