So we have a chevy venture and haven't had any problems with it till now, we were driving it and it starting acting up and just wouldnt start afterwards.

Here are the current symptoms:
-Will start if sitting for a while (minutes to hours) and will start choking and die within a few seconds of starting
-Sometimes after dying it will refuse to start at all, it will turn over just fine

Attempts to fix/Checks/Info:
-Replaced fuel relay
-Replaced an O2 sensor (near muffler)
-Spraying starter fluid in intake allows it to run
-No security light is on during any startup/keyon
I'm thinking its the fuel pump and I plan on checking it with a fuel pressure gauge soon but id like to hear what you guys think it could be?