1995 Ranger XLT 4WD 4.0 OHV
i had two codes P0171 (bank 1 to lean) and P0301 (misfire on cylinder 1). Truck would start fine and idle with just a slight miss but had no power and ran rough while driving. With the engine running at idle I pulled the plug wires from the coil one at a time. All wires had spark at the coil and would alter the idle when removed except #1. It had spark at the coil but no affect on the engine idle when removed from the coil.
It had been many years since replacing the plugs and wires so I started with that.
Installed all new plugs and wires. No change.
Stethoscope test on #1 fuel injector sounded bad so I replaced that next as well as the fuel filter.
Truck initially started right up after priming the fuel system by cycling the key on/off several times. The engine performance was much improved. After two test drives everything seemed good. However, now the truck won’t start without the gas pedal held to the floor. Then when it starts it idles really fast for 1-2 minutes then settles down to normal idle.
visual inspection shows no signs of fuel leaks. Any ideas what could be causing this new issue would be appreciated.

thank you.

 

Did you ever find out what the cause was.