could my fuel pump be going out? they usually dont just go out. usually it happens like this. thats why i was thinking it could be my fuel pump. but i was lookin in the haynes under trouble shooting and it was talking about fuel pump, egr valve and fuel pressure regulator. could this have something to do with my cars idle going up and down once in a while? it will go up to 1500 then drop to 500 over and over at a stoplight, but usually only after the car has been warmed up or driven for a good 1/2 hour