Dear Tom and Ray:

Please save us from the unmerciful Dealership Gods! The fuel pump on my 1986 Saab 900S blew out (literally). My husband replaced it (miracles do happen!) with an identical pump. Now, the pump makes a loud, high-pitched "buzzing" noise, which worsens as the car or outside temperature warms. The amount of fuel in the tank has no effect on the buzzing. My car now idles rough, but otherwise seems to run OK. Fearing the Dealer Gods, he then replaced the pre-pump, the fuel pressure regulator, and the little hose attached to it (just for good measure), but the buzzing persists. My husband thinks the noise is due to air getting into the fuel pump somehow and I just think that it's extremely irritating and indicative that my car is on the verge of stranding me somewhere. Please advise.
Buzz

RAY: Well, we can try to save you from the Dealership Service Gods, Buzz, but not from the Dealership PARTS Gods.

TOM: The problem is that your husband replaced the fuel pump with an IDENTICAL pump. Unfortunately, that car's original pump has a design flaw, and has since been redesigned by Saab. So if you go to the dealership now, they'll sell you a new pump that eliminates the buzzing noise AND the rough idle.

RAY: If your husband is still game, have him go to the dealership and pick up one of the new fuel pumps and put it in.

TOM: Or, if he's so sick of this car that he never wants to look at it again, just take it to the dealership yourself, Buzz. You can face the Dealership Gods. You'll be OK. Just be sure that when you go, you bring the appropriate offering: Lots of money.