I am lost. I have a 96 F150 with a 4.9 and it is running lean. It set codes 0171 and 0174 for bank 1 and 2 lean. I drove it for 2 months with the light on. I pulled the plugs the other day and they were lean burnt. I don't think I got the valves yet. I checked for vacuum leaks, changed fuel filter, checked fuel pressure, checked & cleaned EGR valve, cleaned injectors with a friends cleaner, and am totally lost. The pressure is 43 at an idle and 40 when you brake torque it. The problem started when I put on a FIPK and oil got on MAF sensor. I drove for 1 month with the CEL on from the oil on the sensor. When I cleaned it and reset the KAM and codes they stayed away for a few weeks but then reset it self. Does any one have any idea what I may have missed or what it could be? Thanks

 

O2 sensor? TPS? Fredrick may see this an give you a heads up.

 

I put in new O2 sensors and the TPS test fine on scan tool.

 

I'm not sure, have you looked at the Idle air control valve. It sounds like you've checked everything else so far. With the spout disconnected, what is your timing set to?

 

I timed it by ear the other day and don't know what my timing ended up being. I won't get a chance to check til Thursday. I will let you know. Thanks

 

Take the spout connector loose and use a light. There is a better than even chance that it might be your problem.

 

I had a friend watch while i torqued it up to about 30 MPH and the fuel dropped to about 28psi. I changed pump and it is fine. I checked timing and it was about 10 degrees high with spout disconnected. Thanks for helping.