Ok, The van has had a P0452 code for some time now (1 year) and the CEL was on because of it, but it operated great until recently. My son got gas at some no-name discount gas station and drove the van home OK. The next morning, it wouldn't start at all, just cranked and cranked. It was very cold that morning and I suspected some water in the gas froze and was blocking the lines. Later, when it warmed up, nothing changed, still would'nt fire. I checked the fuel pump fuse and swapped the fuel pump relay with another one of the same type. Still no start. I had it towed to a shop who replaced the fuel pump motor in the tank. It ran well for 3 days and then wouldn't start again. Still suspicious of the fuel, I disconnected the front fuel rail QD fitting and bypassed the fuel pump relay to pump out the fuel tank into a storage container. It pumped about 4 gallons of gas in about 5 minutes time, telling me the fuel system was good up to that point. I put in 5 gallons of good fresh gas and tried to start again. A few times, it did start but stalled right away. The next day, I started it again. it ran rough for a bit and then smoothed out nice at around 650 RPM. If I tried to give it some gas, it would falter and stall. At that time, my code reader showed the P0452, and the "O2" light on the reader was lit. I then replaced the upstream O2 sensor with a new one. No difference. When it does start, it will idle smooth for a while, but after 2-3 minutes, it will start missing and die. Any throttle above idle will kill it as well. I disconnected the battery
for 1/2 an hour to wipe the PCM clean thinking maybe there were corrupt values in memory but again, no difference. It still wont start most of the time, and only at idle when it does. I have a MAP sensor on order, but I'm not sure that will help either. With such gross symptoms, I still only get the P0452 error on my scan tool.