03 Neon sxt 2.0 sohc automatic p0171

If you're getting it from the Snap-On site, it should be fine. That's where I got mine

ok, I've tried to add pictures 3 times now and it appears that the computer uploads them but then my post doesn't exist on here.

There are some issues with the site right now. Apparently there was an update that caused a bunch of issues, including log-in problems.
Wyatt (my web designer) is working on it now.

SO, I believe I have the issue FIXED!!!. Just over a year only. Well if anyone is interested I will try not to give the answer so you can guess what the issue was. Originally The car would idle at normal trims. Snap throttle at idle normal as well. After I put the car in D as soon as I would touch the gas pedal even a little the trims would max out almost instantly. It was weird that it would only happen while driving.The p0171 freeze frame data only ever showed the code happening at idling rpms and 0 mph, even though the trims were maxxing out while driving (+33 short, and long term), that was always confusing to me although I know the monitors happen at certain conditions per manufacturer. So, I took the car in to the major auto electric shop in the area, maybe in Western Pa. I trusted them because they accurately diagnosed a bad pcm on my s10 once that wasn't allowing the transmission to shift. They told me the fuel pump on the neon was bad, that the pressure guage was showing ~30psi. I took the car back to my dad's garage and put a gauge on the fuel rail and seen the 30 psi. The thing is if I unthreaded the guage a little from the rail the pressure would go up. So I knew it wasn't the pressure but rather a problem with the guage/rail. A couple different makes of gauge and finally I got one that showed the actual pressure. I pulled the plugs at one time and they looked lean(very white), so I figured the car really was running lean. The car would sometimes idle rough especially after driving and stopping at a light, etc... I would unplug the o2 sensor and no change. The car felt like it had a fuel supply issue because sometimes while cruising I could feel a little extra power kick in. I have messed with the car for a year trying to figure out what's going on. Within the last couple months I would notice that after driving it and parking it at home at idle the upstream 02 would read very lean like .1V and sometimes around .055, just like when driving. When it did this at idle I noticed if I turned the ignition off and restarted the car the o2 sensor would start reading again. I thought it was a computer issue, maybe a bad driver. My rear o2 sensor heater circuit is always at 100% DC so I thought that could be affecting the upstream circuit as well or the computer. I had injected propane into the manifold with the upstream o2 unplugged of course because when I injected anything into the manifold with the sensor plugged in the car died instantly which made me to believe the sensor was working. Unplugged the sensor went full rich(checking with my DMM). I also delved into fuel pressure. There is mis-info ( the only info) on the internet that says that fuel pressure on a neon should be 49psi. I had to subscribe to ALLDAtaDIY to find out that on the second gen neon (my car) that pressure should actually be 58 psi +/- 5 psi. The car only had 49 so I dropped the tank to see if I had a bad regulator/filter or fuel pump. I had done snap throttle like Danner shows in his videos and notice a couple psi drop if i snapped the throttle a bunch of times real fast. So I wasn't sure if that was acceptable and pulled the regulator. I tested using air and a vacuum guage and the regulator put out 49 psi. Problem solved!!....I thought anyways. I replaced the regulator with a junkyard unit (not the best I know, but when changing parts...) The regulator that was on the car originally must have been from a gen 1 because it was stamped 49 psi. I put the one from the junk yard in and put the tank back in and now I had 58 psi. Here's the deal, I took the car for a ride and while cruising the fuel trims looked good but at idle the trims were maxxing. NOW, I was really confused! The problem moved with the part (trims changed with the replacement part). The car started idling rough again. I unplugged the upstream o2 and the car idled fine. The car also felt like it was losing fuel with the car in park and high rpms, I could feel "power" reduce like the car was losing fuel. I figured it was from maxxed high fuel trims at idle to trims lowering at rpms and maybe this was the reduced fuel feel. I decided to do a comparison today by holding the throttle while parked and waiting for the reduced fuel feel and then to unplug the o2 sensor and see if the feel was there again. I figured pressure loss is pressure loss not matter if the trims are maxxed or normal. The only problem is I didn't get that feel today. The car also started idling rough and I unplugged the o2 sensor without any change in idle. I also changed the map sensor (not as a part's changer) but because I compared scanner data with actual pressure on my vacuum gauge and didn't have enough knowledge of what I though the problem was, I changed it in vain. I also replaced the ignition coil because when I got the car it had some corrosion on it and I figured even if it didn't fix the problem the car would need it for healthy spark. So that was kinda being a parts changer but I viewed it as a maintenance item (good excuse??). So after replacing a part today I took the car for a ride and trims look good, every once in a while if I snap the throttle at idle I will get around a +10% fuel trim but only occasionally. So far I consider it a fix. Take your guess at what it was and I'll tell you why I came to the conclusion that I did (with 50% certainty).