I have a 93 trans am that keeps eating fuel pumps. The first one went bad in 80 miles and I was told it was because the sending unit was bad so I replaced that and it was fine for 1300 and then it went out now I had this one put in two weeks ago and its been 300 miles.

It drives fine then all the sudden at a quarter tank I hear it start buzzing bad and it starts cutting out. I pull off and get some gas and it seems better but is still louder and not the same when it does it. I dont think its only when my fuel hits that low but it might be. I asked mechanic to check voltage and current and he said they were normal.f

Check that your return line is functioning. Some Electric fuel Pumps can not withstand blind end pressure.

walbro pump.

I'm having trouble with it still today. It seems that if I turn the car off and start it back up its fine but when the thing starts sitting for awhile in traffic or driving a long time it does the same thing drops pressure all the sudden almost completely and starts getting really loud.

Also pressure checked out when installed so return line cannot be plugged.

Install one of these and you're set. http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY-12-802-1&N=700+4294925239+4294839053+4294836965+4294891680+ 4294891681+115&autoview=sku

thats a max of 14psi the trans am stock runs upwards of 40

ooops. sorry about that. I was thinking carb'd for some reason. Even at 40+ psi you can get a nice fuel pump and get away from the AC Delco stock stuff for a decent price. I'm just basically trying to give you an idea and maybe have you go in a different direction if the OEM stuff seems to be failing. Mallory (http://store.summitracing.com/partdetail.asp?autofilter=1&part=MAA-4060FI&N=700+4294925239+4294839053+4294836965+4294891680+ 4294891681+4294782648+115&autoview=sku)makes a nice pump.

Sounds like a heat issue. This would also explain why it seems to fail when the tank is low. Fuel is what cools the electric pumps. Is this an in tank pump?

Check the fuel pressure during the whole driving cycle, and watch for any high readings when the fuel pump gets loud. This could indicate a pressure regulator that is sticking or a return line restriction. I would not only check voltage and amperage, but you need to check resistance in the circuit. I know you said you asked your mechanic to check the current, but that doesn't mean he did or even knows how to (not trying to disrespect him, but you would be surprised how many don't). I have seen many GM fuel pump wiring pigtails that have been hot and burnt. This will cause the pump circuit to have high resistance and will cause the exact problem you are having. I don't think you are getting bad fuel pumps, there is probably another underlying problem that need to be found and addressed.

We put a new pump in ac delco and didnt change anything. Everything looked fine new pressure regulator and the pigtail looked brand new as the sending unit is new, the tank is new, the fuel lines are new, the regulator is new and injectors are nw. The voltage was check under the car. He said current doesn't matter.

I dont know if this matter's or not but I wired my heated o2 power wires into the pink wire coming out of the computer which is apparently for fuel related things but when I disconnected the wires it didn't change how the pump acted and they have been on there for 7k miles.

He was talking to some people though and apparently there has been some issues with walbro burning up like this in the area. He got the fuel pumps on the same shipment and he thinks the shipment of pumps were bad because a few other mechanics just had a bunch of wallbros go out.

"He said current doesn't matter." You need a new mechanic. If he said that current doesn't matter, he has no idea how an electrical circuit operates. I'm not trying to be pious or rude by my statement, so please don't take it that way. I am a mechanic by trade, specializing in drivability issues. In my 20 plus years I have had only one or two fuel pumps fail prematurely. But I always check my current, resistance and voltage to verify that I won't have a return. I'm not saying that lack of current is your problem, but it can't be eliminated as a possibility until it is tested by someone that has a through knowledge and understanding of electrical theory. If you do a google search on Ohm's law, you can get a good idea of how electrical circuits work. You can have proper voltage in a circuit, but have too much resistance in the circuit. The resistance will "starve" the circuit of the proper amount of current it needs, and will overheat the component and it will ultimately fail due to the heat. One more thing you didn't mention was whether a new fuel filter was installed. A plugged fuel filter will also cause excessive heat in the pump and cause it to fail. I know it may seam a no brainer to assume that there is a new one, but I've learned to never assume anything. I doubt that walbro has a major problem with fuel pumps burning up. I recently read in one of my trade magazines that all brands of fuel pumps have about the same failure rate, and they all have a very high failure rate due to poor workmanship. Not by the manufacturer, but by the shops installing them. I hope you find your problem soon. Tom