New fuel pump, now p0440

Lil background.
April I had a p0440 code and they replaced the purge solenoid.
In July I had a shop put a fuel pump in....shortly after I got a P0440. They said they forgot to hook something up, hooked it up and seemed fine. According to them the truck would check around 1/2 tank and throw the code.
I had trouble starting it last week, so I went back to them and the new fuel pump needed replaced *it was under warranty*. Problem is, now that they have replaced it, this time with ac delco..I only went 40 miles, was at 1/2 tank and have got another p0440 code!

Do you guys think its possible they forgot to hook something up again or what do you recommend checking into? I also just had the intake gaskets replaced during this time too. The gas cap was replaced a few times since Ive had it. I have spent so much money on this lately and been inconvenienced while its gone into the shop time and time again. If they tell me its something else that costs more, yaw might just see me on the evening news.
In my next life I'm marrying a mechanic =-Þ
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4.3 ... 88,000 mi

That trouble code indicates the inability of the evaporative emissions control system to draw a slight vacuum on the fuel system. That can be due to:

1. A failure of the vacuum control system (including the aforementioned purge control solenoid valve);

2. A failure of the tank sealing system, including the gas cap, purge lines, fuel tank top unit seal, evaporative emissions vapor canister, or fuel filler neck fill and vent hoses;

3. Or a failure of the sensor which monitors the fuel system pressure. There is a pressure sensor mounted on the tank top unit (which is replaced when the fuel pump is replaced).

The tank pressure sensor could have been left disconnected, or the purge solenoid could be disconnected. The seal at the new tank top unit may not have sealed completely, or the vacuum lines to the tank, the Evaporate Emissions canister, or the purge control solenoid valve could be damaged or disconnected. In any event, I'd suggest returning the vehicle and asking them to repair whatever it is they forgot when replacing the fuel pump the last time.

Thanks Blue.

I took it to them this morning and they called me a short while later and said something was left disconnected, I didnt ask what..at this point I just want it fixed and in MY garage.
I want to go to a different mechanic but for now it keeps going in for things they did so I go back since the cost is covered by them kwim?

I hope this is the end of the dreaded P0440 code, that thing has been a major pita.

Only way to find it is with a smoke machine.There is a test port for this in the engine compartment,look for a green cap.Remove the the green cap and there is a schrador valve to remove which removes one way.There are a couple companies that make smoke machines including Snap On.The problem with the Snap On smoke machine is that you have to use their oil which is not cheap.The other smoke machines use baby or mineral oil which is cheaper to use.