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Hi everyone I’m trying to find some help for a buddy at work. The other day he drove his f150 to work with the low fuel light on and on the way home stopped and threw in 20 bucks worth. Continued on his way home and it started to run very rough and check engine light came on. It shut off. Still ran rough and came back on and now is flashing. I pulled the codes and get P0171 and P0302. Freez fame was about 2200 rpm 62% load and ltft was 25%. Now what. Bad gas. Clogged fuel filter or unrelated to getting gas or maybe a week fuel pump. Any one have any thoughts
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Well, my .02 says to start with change the fuel filter especially if it’s been a while. I like to change mine every fall. Secondly, swap the # 2 coil pack with another (#1 or #5 is prob the easiest) and see if the problem cylinder follows the coil pack. Right around 200k my 5.4L coil packs started dropping out.
Ya I was just wondering what the chances of low fuel pressure making one cylinder have a dead miss. Or maybe both codes were caused by an ignition issue. And I going to say the truck has well I’ve 300000 km on it. I was thinking that a low fuel pressure would give a random miss fire
Thanks for the help. I’ll switch the coils and go from thereWell, weak fuel pressure and random misfires, it could happen… As in NOT ENOUGH fuel in the combustion chamber to ignite. But, you don’t have random misfires (randomly across all 8 cylinders). You have a very specific misfire, P0302, consistently in cylinder #2. The flashing CEL is an indication from the O2 sensors that the exhaust is way too rich. Think TOO MUCH unburned raw fuel going out the exhaust… For example, as in a fully functioning fuel system and a dead spark plug…. or ignition coil. Further, it’s been thought that this unburned raw fuel scenario could become a runaway freight train and by extremely rapid switching of the O2 feed back to the PCM interpret a lean condition (P0171 also bank #1), whereby PCM increases even more fuel flow.
So, just saying it’s fairly painless, quick and cheap test that can tell you a lot whether the problem cylinder moves with the COP or not.
Problems solved well maybe not. Last night before he left work is when I red the codes and freeze frame data and I cleared the 2 codes. On his way home the check engine light was on solid and into the drive a it it started flashing a couple of times and went solid again and then shut off and he said when it shut off the truck ran fine actually as if nothing was ever wrong with it. I have no idea what to make of that I thought for sure the cop was gone and maybe the plug on cylinder 2
The truck runs good now no work done and the only thing I can think of would be the connection for the cop. Maybe loose or corrodedLOL, yea my people kinda get miffed at me when I say if we didn’t fix anything, it’s prob not fixed. OK, kewl. lemme know.
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