I always recommend determining if something is bad before replacing it unless the item is inexpensive and easily replaced. In the case of the fuel pump it is neither. The fuel pressure is specified in the thread I referenced. If your pump is bad I'll give you a link to a thread on how to replace it. Other possible sources of your symptoms that come to mind: MAF sensor, crankshaft position sensor, bad fuel, ignition coilpack, synchronizer, clogged intake hose/filter.