Lean Mixture, Fuel Injected...?

Question

What are the most common causes of a lean air/fuel mixture in a fuel injected vehicle? 94 Celica with erratic idle and stall issues.

(Replaced fuel pump, fuel filter, spark plugs, wires, distributer, rotor, cap, coil, fuel pressure reg, ECM, and more.)

P.S. please don't say go to a professional... tried that and I am $1,500 more broke than I started and no further with the issue.....

Thanks for any advice.

Answer 1

Idle air control would be one cause. A bad temp sending unit or O2 sensor. Your really have to hook up a scanner to that vehicle and get the live data and see whats causing this problem