98 GC code PO171 Lean condition

What would cause a lean condition that would trip this code and make the vehicle run rich? (lousy gas mileage, but no driveabliity problems) I need the flow chart to assist in solving this. What are the sensors that would affect the lean condition.

Have the Throttle Position Sensor checked, that was my problem on my 2001 GC. Good luck.

Bank one sensor one lean condition. Could be bad Ho2s, Map sensor, IAt sensor, Fuel pressure, bad injector,Egr, Catalytic converter and Ignition. Hard to do diagnostic with out a Scan Tool. Need to read the fuel trim numbers. this probally wont help too much unless you can access a Scan Tool to see whats going on.

Well I did get it fixed. The GC has 165K on it so sensors were suspect with soooooo many miles.
I first replaced the coolant temp sensor. There was no change, but we did observe that as soon as the Jeep was warmed up the mileage dropped. That led to replacing the pre converter Oxygen sensor, which does control the fuel mixture. With that replaced and the codes cleared the fuel mileage is back to normal.
I did check the simple things first, usually that is all that is wrong.