E-150 Ford Van 1999 service engine soon light

service engine soon light on,changed spark plugs,2 o2 sensors,egr valve.-after warming up runs rough and when in gear at a stop light will stall sometimes but when nutral would run better.

What diagnostic codes showed up?


i belive 171 to lean

i cleard the memory and have to wait for it to show up again

Would you believe, it REALLY is running too lean?!

yes a little ,but what to do?It ran better for a while after clearing the memory and im going to check the code today.the idol speed cant be adjusted on this van.

The first thing to do is to verify the code.

If it is P0171 (system lean on bank 1) then the first thing I would do is clean the mass airflow sensor. Then I would check for vacuum leaks. Then I would replace the fuel filter and check the fuel pressure. These are cheap and easy things that often work.

Can you better describe “runs rough?” Does the idle surge & fall/surge & fall? Or what?