Hey all, just bought my first Ford today. 1995 5.8l V8, 149xxx miles. Ran fine until about an hour back on my trip, it seemed to hesitate after I came to a stop and then put my foot back on the gas, and the CEL would turn on and then turn off. Got home, parked it and then started it back up about an hour later and it'd start sputtering after being idle for about a minute and seemed to just about stall out. I checked the error codes and got a stored 172 lean fuel mixture back. I'm not really sure where to start in terms of replacing parts or doing tests, any assistance? Thanks!

 

Don't replace ANY parts until you pinpoint a fault with a part. But you haven't even begun diagnosis. You haven't even found the correct code definition. Read this whole caption (a few times, if necessary):

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If you want more help, read this one, and then put ALL the truck's details into your signature:

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172 is an Oxygen sensor code - but it doesn't necessarily mean you have a bad O2 sensor. More often than not it is a vacuum leak or a problem with the FPR/fuel delivery system. Sometimes its just a dirty connector on the O2 sensor itself, because it lives in an environment where it is likely to get covered in grime and oil from anything leaking in the engine, especially the oil pan/rear seal.

 

I did some digging around and found an exhaust leak on the muffler, my guess is that oxygen is leaking in through the hole and messing with the readings on the O2 sensor. Fuel pressure is right where it should be and I haven't been able to find any vac leaks so that's all I can think of now. Does that seem like it could be the culprit?