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P0171 Code that won’t go away

Posted: September 26th, 2023, 6:41 am
by babcockscott1102
I bought a 97 Jeep Wrangler with 4.7l stroker last fall and I’ve been fighting this code since January. I’ve fixed vacuum leaks, replaced a bad MAP sensor, upstream O2 sensor went bad and was replaced in January. Didn’t realize you should replace O2 sensors in pairs until recently. Downstream was bad and replaced it last night. Cleared all my codes after replacing the sensor and let it run / drive it for 30mins, no new codes until this morning. Code came back less than 5 mins in my drive. Below is the freeze frame. Any ideas what to do next?

Fuel System Status
CL
Calculated Load Value
14.5%
Engine Coolant Temp
198.8°F
Short Term Fuel trim – Bank 1
31.3%
Long Term Fuel trim – Bank 1
32%
Intake Manifold Absolute Pressure
3 inHg
Engine RPM
1472

Thanks in advance for your help

Re: P0171 Code that won’t go away

Posted: September 26th, 2023, 1:22 pm
by Muad'Dib
Sounds like your code came back after a cold start?

Two things I would check:

Fuel Pressure Regulator. Hopefully whoever build the Stroker put on an Adjustable Fuel Pressure Regulator. I would adjust to give you a bit more Fuel Pressure.

Fuel Pump\Fuel filter. I would make sure its a good filter and ensure the Fuel pump is not dying. If you are only seeing this on cold start, its likely not the issue, however its still good to check your Fuel Pressure.