I just bought this 99 f250 super duty with 197k.
I changed all fluids and installed new spark plugs. I then changed the exhaust. I deleted the cat and replaced my muffler with a glass pack. Right after that I got a P0171. The pickup runs rough and jerks when driving it.
I cleaned the MAF sensor. I did replace the fuel filter. I check the pvc hose under the throttle body. It looks good.
What other hoses do I need to look at for vacuum leaks? I have read that it may be my O2 sensor.
It ran pretty good until I changed the exhaust. I did add some marvel mystery oil at the same time.
I did clear the code but still runs rough.
My 4x4 light, service engine light does not come on when I turn the key on. All my other light come on then go off. My check engine light never comes on either.
My ABS light is on but I know what the problem is their. The left front wire going to the sensor is broke.