1998 F150
5.4
159000 miles

Ok so I've had my check engine light on here for about 3000 miles, ran the numbers took it in, it was a bad bleed valve on my fuel pump. However at the time I didnt have time or money to replace it so I was waiting till next monday. Well on my way home the check engine light started flashing so I turned it off, opened hood, let it sit then started it up and it stopped flashing.. What does this mean? As of now I am no longer driving truck till I get the problem worked out.

 

A flashing CEL is almost always a COP going bad.

 

When the CEL flashes it means the problem is immediate, as opposed to vacuum leaks, misfires or dirty sensors that set a solid CEL. Either way you need the codes pulled before we can say what the problem could be.

 

A flashing CEL is the PCM's indicator that you have a SEVERE misfire - most often caused by a failed COP as torkum said.

Pull the codes - the DTC will tell you which cylinder(s) may be suspect.

 

What's a COP?

 

Coil-on-Plug