P0171 Ford - ranger

Question

I have a 2004 Ranger 2.3l. The light came on while I was driving in -30℃ and the engine didn't warm up anywhere near fast enough. (Replaced the thermostat and flushed the fluids)
The first owner did make his own "cold air intake" by ripping out the airbox and hose-clamping a cone filter to the MAF so it could have cracked.
Aside from that the truck runs famously, albeit sometimes a little rough if the batteries been reset which leads me to believe it's something minor.

Answer 1

Hi there,

It may be the maf sensor causing the code. Since you are resetting the fuel trims with the battery reset, it might be a tad bit rough because the maf sensor is giving the wrong reading and causing a lean mix. If the maf is good, then the front O2 sensor could be the most likely cause because you aren't having any running issues.