2001 5.4 4x4 truck has been running fine but when I started it last night it ran very rough, like it was only running on 6 cylinders. check engine light would flash rapidly and then turn off, it did this several times. checked it with a code reader this morning and it hasnt thrown any codes. Has had the same gas in it for several days so I doubt its bad fuel. new filters and tune up last fall. truck has 160,000 but is maintained well and hasnt had any problems until this. Any ideas on what to check?

 

I'd put some Heat or Sea Foam in the tank. May have got some water/condensation in there somehow.

 

ave you checked to see if the mass air flow sensor is clean?(no dust build up) & also check to see if the throttle plates are clean at the throttle body