How to Diagnose Faulty Fuel Pumps

1. Take your car onto a highway and travel at the posted speed. If the engine in your car occasionally misfires, you will notice a slight hesitation. A faulty fuel pump, particularly in the first stage of failing, frequently will falter a time or two then your engine runs smoothly for miles. Even a professional mechanic can misdiagnose the problem and recommend a tune up or a fuel filter instead.
2. Get behind the wheel of your car and press the gas pedal. If your car momentarily fails to accelerate, you probably have a fuel pump that's about to stop working. Often seasoned mechanics mistake a failing fuel pump for an oxygen sensor which is less expensive to replace than the fuel pump.
3. Start the car. If it doesn't start right away, don't rule out a faulty fuel pump. It won't start because the engine is robbed of the fuel it needs to do the job. Besides a faulty fuel pump, it could be caused by a myriad of reasons, including the timing belt or the fuel filter. Before you spend a substantial amount of money getting a new fuel filter installed, you would be wise to get a second opinion.
4. Climb a hill in your car and if you tend to lose speed, it is probably caused by a fuel system failure, with the fuel pump being a prime suspect. Often a fuel filter is all that needs replacing, but the fuel pump is a possible candidate for replacement.