1999 Ford expedition 5.4 liter. truck ran rough no codes.

Question

I have a 1999 Ford expedition 5.4 liter. The truck started to run rough but had no codes. It then died and would not restart. Still no code. Got vehicle home and it started. Next day ran rough, did not have a check engine light but had code PO112 Restarted code was gone. Truck again stumbled and died but restarted again no check engine light but code PO123 PO451 AND PO412 existed. Next morning started truck codes are gone. While driving temp gauge when to full hot but scanner showed temp of 199 deg. Shut truck off restarted gauge reads correctly. While backing the truck up ignition cut out and the truck died, restarted again no check engine light but code PO320 Distributor engine speed input. This one made sense but all the other codes and the temp gauge don't Unless all these circuits are sharing possibly a common ground?? Or could it be the ECM ground or ECM internal ground?? Any help would be greatly appreciated. Thank you

Answer 1

P0320 Ignition speed input circuit

P0112 Intake air temperature circuit low input

P0123 Throttle position circuit high input

P0451 intermittent condition (ignition)

P0412 Secondary air injection

Throttle position sensor high input means your basically disconnected, and with the vehicle stumbing during a cold start up with a false temperautre reading , This may be a faulty ground, If you want to check for a faulty ECM ground use the DLC connection measure pin 5 and body ground with the engine posible running, Your volt meter should not measure more the .5 volts, if it does you have a insufficient ECM ground, Or you can ground the ECM  using pin 5 at the DLC (diagnostic link connector).When you turn the key on you should hear relay come on, and the fuel pump start, This is imposrtant, the PCM relay needs to come on.  One of the test you should perform is what Ford recommends and that is a wiggle test, it is possible if you ever wahsed the engine the connection or the engine harness will make a poor contact,simply disconnect and reconnect usually solves harness connection probems