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p0171, 300, 301, 302,316 all at once. Suggestions?


sickwilly

Well-Known Member
Joined
Mar 31, 2017
Messages
96
Vehicle Year
2003
Transmission
Automatic
Ok so running normal, then suddenly starts sputtering and running like crap. I just happened to be near a friends house and was able to make there and not leave it on the side of the road. This was within 3 miles or so. Did this exact thing a few years ago and it was the spark plugs. So I changed em again, that aint it this time. I have an odb link scanner and these are the codes it threw (this is after clearing old codes). I can just go ordering parts, but thought id see if anybody had any suggestions.
p171, lean bank 1
300, random misfire
301, misfire cyl 1
302, misfire, cyl 2
316, misfire at startup
problem seems to be on one bank only, am i wrong? Im wondering if coils fail on one side only? Any suggestions appreciated.

Ignition coil, o2 sensors, injectors. Im unsure if o2 sensors would make the truck undriveable.
 
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What are you driving and what engine
 
Its the 03 xlt in my sig. My bad.
After it sat for 1 1/2 hrs, it crunk and ran fine again for about 10 minutes. I took it down the road a couple miles and it started sputtering again. That kinda tells me its not a clogged fuel filter or a clogged injector or a vacuum leak.
 
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check power to the injectors.
while the PCM grounds individual injectors to open them, they all have a common power source.
 
““RonD
Jun 6, 2023
Yes, with MAF unplugged computer switches to Open Loop so no longer does the air/fuel calculations, and ignores O2 sensors, just runs engine on Factory tables for that engine size, same as it does when engine is cold

With engine warmed up and idling
Unplug the 2 wire connector on the IAC Valve
Idle should drop to 500-600rpms(barely running) or stall, either is GOOD it means no vacuum leaks
If idle doesn't change then there is a leak”””

Quote above is from another thread but this seems like an easy way to check o2 sensor.
 
Misfires cause Lean codes because misfires do not burn up any Oxygen
So misfires on 1 and 2 cause Lean code p0171(too much oxygen on that bank)
So P0171 is not part of the problem
P0171 System too Lean (Bank 1)

You changed spark plugs but what about the coil pack last time?
P0300 and P0316 tend to occur when coil packs get cracks in them, or spark plug wires are more than 15 years old
 
Im heading over there now to hopefully find out more. Plan ordering coil and wires if i dont find anything else.
 
Its the coil. I put a coil in from a 2002 and it ran fine for the 30 or so miles home.
Are Motorcraft coils and wires the best bet?
 
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