Yes it is a long post, but I wanted to explain everything and I couldn't help it......I posted this in another forum, no responses in a few days, so I'm going to a different town and country (pun intended) to see if someone might have a good idea here. 2004 Grand Caravan with 133k. I replaced the oem fuel pump (probably unnecessarily) over 2 years ago @ 100k miles because I heard a different sound from the oem pump with the key "on" at that time. Online consensus is if you start hearing different sounds from your fuel pump, it may indicate impending failure. I also wanted to change the fuel filter, and I knew the only filter was on the pump, the "sock" as it is called, all conveniently IN the tank... I checked my pressure before and after replacement of the pump with a harbor freight kit, which is another long story. This vehicle has no convenient port on the fuel rail for the pressure gauge. (You have to make your own test port. I replaced a plastic straw fuel supply hose right by the fuel rail with a piece of rubber fuel hose, fitted with the in-line T adapter in the harbor freight kit, tightened down with hose clamps. I got a plug to use in the port where the gauge goes, so now I can check the fuel pressure whenever I want by removing the plug and screwing in the gauge) So in 2017 I replaced my oem pump with a made in China delphi unit from Autozone. My tank was clean, and my oem sock filter was in very decent shape. I changed it out and was happy for the piece of mind of having a new filter and pump for any long trips that we take, but I was still uneasy about it being made in China. I also noticed that I occasionally was still getting different whines from the fuel pump. Sometimes I didn't notice anything and then after a few weeks it would make a groaning sound when I turn the key. ugh! I decided that the different sounds may be from having low to full tanks of gas muffling the sound and thought perhaps sounds mean nothing and I really didn't need to replace the oem pump in the first place. We did a road trip from NY to Florida in 2017, 2018 and now again in 2019 with this vehicle with that delphi pump. We stopped at our hotel and 10 minutes later we get back in the van to go to the beach and a quarter mile down the road the thing stumbles and dies. I have an ultragauge which plugs into my obd-II port, worth every penny. My boys got out and pushed us off to the side of the road and I got a code p0171, which means lean condition bank 1. V-engines have 2 banks, but since we only have one pre-cat o2 sensor, this code cannot really know which bank is having issues. I tried after a few minutes and thankfully it started, so I quickly made a U-turn to head back to the hotel and it started stumbling, and stalled as I pulled into an entrance off the road again. After a few minutes I restarted and was able to make it back to the hotel, again stumbling after 2 minutes of running to a stumbling stop in the parking lot. I popped open the hood and what I immediately noticed was the intense freakin' heat in the engine compartment. We were running the AC, and it was 103 degrees outside, but the heat when I popped open the hood was insane, like a barbeque. Temperature gauge was normal. The sound of the fuel pump was also an intense groan and whine with the key on, much louder than normal. I left the hood cracked open. Two hours later, I tried it again and it started just fine. I thought perhaps bad gas at our last fillup, perhaps fouled fuel injectors after 1250 miles of driving. Ok let's go get some fuel injector cleaner and go to the beach. I dumped seafoam in the tank and went to the beach and got back to the hotel uneventfully, not using the AC. I also got another fuel pressure test kit at the local harbor freight for $16 with their 20% coupon and a free flashlight 
...The next morning I tested my fuel pressure. Gauge shot right up to 58psi and held at 55 very nicely with key on/engine off. I was convinced it wasn't the pump. I would think a failing pump would show lower than normal pressure. All local 10-15 mile trips were then uneventful. Now on the way back home to New York, 55 miles into our trip back, using AC, it was 101 degrees outside and it started sputtering on the road. Watching my ultragauge live sensor data, o2 sensor #1 was dropping to near 0, and the o2 sensor #2 was following as lean as well. I knew o2 sensors were not bad then since o2-2 was following the same lean condition a couple of seconds after o2-1. I pulled into a parking lot and again the heat in the engine bay was incredible. I went to try to get a fuel pressure test done and could not touch the fuel hose T-fitting for more than a second it was so hot. I let it sit a few minutes and braved the heat to attach my gauge. Gasoline was bubbling, boiling in the test port. Engine was started, pressure jumped from 0 to 55psi, and after about 10 seconds of running, pressure fell down pretty quickly, not suddenly though to 10-15. It sputtered, but continued running. I shut it down and waited. Engine off, as I was removing the gauge, I squirted gasoline and saw the pressure drop to 0, hot gasoline started dangerously firing out in all directions so I reattached the gauge, it climbed to 10-15psi. 3 times in 2 minutes I did this. What the heck? Fuel rail too hot to touch still. Fuel boiling in the line raised the pressure in the fuel line with the key off. I thought vapor lock but the pump is supposed to maintain 55psi regardless of air in the line. I knew for sure a fuel line is not supposed to be that hot though... I could not hold my fingers on the metal fuel rail, or the 4 inches of rubber hose that attached to it. I saw then, that the fuel pump apparently was not working at all when it sputtered, and the boiling gasoline from the heat in the fuel line was what was showing as 10-15psi when it was sputtering. Hoping that somehow vapor lock would prevent even an electric pump from working well, I did a little improvisation to get some air to flow through the upper engine compartment. After some 20 minutes of cool-down, I removed the left rubber tubular baffle thing on the hood lip and just clicked the hood down, not closed all the way. I drove, carefully watching my live o2 sensor readings. That left a nice open slot for air to get channeled right into the top of the engine. Engine hiccupped once after a few miles. After 20 miles or so at the next light in Alabama (some countryside where I certainly did not want to be run down), it sputtered but did not die. O2 sensor 1 did some long dips into lean territory, but bounced back. I continued and thankfully it was running just fine after that. Temperature outside was dropping and I didn't dare operate AC. I was thankful for any miles I could get and was getting more confident as time went on. When I stopped for fuel some 200 miles later, I could touch everything in the engine compartment. Fuel rail was barely warm. What happened 200 miles ago? Why didn't I have a constant 55psi when on, even if I was vapor locked up at the fuel rail with a 3/4 full tank? Is it possible that the fuel pump is sporadically bad? Perhaps my fusebox and/or ecm getting roasting hot in the engine bay warps enough for a bad connection? Fuel pump relay failing with heat? Is it so darn hot in the engine bay when using the AC because of the heat coming off the condenser getting trapped? If it is not a heat trapping issue, how can my fuel rail be so darn hot, and then barely warm 200 miles later, and the next 1100 miles home? I gotta say it ran fine all the way back home with my hood air scoop setup, but I got 21mpg all the way as opposed to 23.5mpg on the way to Florida. I have seen people online talking about egr causing the stalling and the p0171, but I am not convinced. Could be fuel pump, could be ecm, could be fusebox, and heat could be the cause of any of those items going bad I guess. My fusebox looks very clean, what do you think? My fuel pressure is again perfect here at home, and a nice sounding pump with it. When I stumbled, the pump was way loud.
...The next morning I tested my fuel pressure. Gauge shot right up to 58psi and held at 55 very nicely with key on/engine off. I was convinced it wasn't the pump. I would think a failing pump would show lower than normal pressure. All local 10-15 mile trips were then uneventful. Now on the way back home to New York, 55 miles into our trip back, using AC, it was 101 degrees outside and it started sputtering on the road. Watching my ultragauge live sensor data, o2 sensor #1 was dropping to near 0, and the o2 sensor #2 was following as lean as well. I knew o2 sensors were not bad then since o2-2 was following the same lean condition a couple of seconds after o2-1. I pulled into a parking lot and again the heat in the engine bay was incredible. I went to try to get a fuel pressure test done and could not touch the fuel hose T-fitting for more than a second it was so hot. I let it sit a few minutes and braved the heat to attach my gauge. Gasoline was bubbling, boiling in the test port. Engine was started, pressure jumped from 0 to 55psi, and after about 10 seconds of running, pressure fell down pretty quickly, not suddenly though to 10-15. It sputtered, but continued running. I shut it down and waited. Engine off, as I was removing the gauge, I squirted gasoline and saw the pressure drop to 0, hot gasoline started dangerously firing out in all directions so I reattached the gauge, it climbed to 10-15psi. 3 times in 2 minutes I did this. What the heck? Fuel rail too hot to touch still. Fuel boiling in the line raised the pressure in the fuel line with the key off. I thought vapor lock but the pump is supposed to maintain 55psi regardless of air in the line. I knew for sure a fuel line is not supposed to be that hot though... I could not hold my fingers on the metal fuel rail, or the 4 inches of rubber hose that attached to it. I saw then, that the fuel pump apparently was not working at all when it sputtered, and the boiling gasoline from the heat in the fuel line was what was showing as 10-15psi when it was sputtering. Hoping that somehow vapor lock would prevent even an electric pump from working well, I did a little improvisation to get some air to flow through the upper engine compartment. After some 20 minutes of cool-down, I removed the left rubber tubular baffle thing on the hood lip and just clicked the hood down, not closed all the way. I drove, carefully watching my live o2 sensor readings. That left a nice open slot for air to get channeled right into the top of the engine. Engine hiccupped once after a few miles. After 20 miles or so at the next light in Alabama (some countryside where I certainly did not want to be run down), it sputtered but did not die. O2 sensor 1 did some long dips into lean territory, but bounced back. I continued and thankfully it was running just fine after that. Temperature outside was dropping and I didn't dare operate AC. I was thankful for any miles I could get and was getting more confident as time went on. When I stopped for fuel some 200 miles later, I could touch everything in the engine compartment. Fuel rail was barely warm. What happened 200 miles ago? Why didn't I have a constant 55psi when on, even if I was vapor locked up at the fuel rail with a 3/4 full tank? Is it possible that the fuel pump is sporadically bad? Perhaps my fusebox and/or ecm getting roasting hot in the engine bay warps enough for a bad connection? Fuel pump relay failing with heat? Is it so darn hot in the engine bay when using the AC because of the heat coming off the condenser getting trapped? If it is not a heat trapping issue, how can my fuel rail be so darn hot, and then barely warm 200 miles later, and the next 1100 miles home? I gotta say it ran fine all the way back home with my hood air scoop setup, but I got 21mpg all the way as opposed to 23.5mpg on the way to Florida. I have seen people online talking about egr causing the stalling and the p0171, but I am not convinced. Could be fuel pump, could be ecm, could be fusebox, and heat could be the cause of any of those items going bad I guess. My fusebox looks very clean, what do you think? My fuel pressure is again perfect here at home, and a nice sounding pump with it. When I stumbled, the pump was way loud.
