Check Engine light flashing randomlly driving
 

'89 F150 300 Straight 6, C6, 62k miles

Been doing it for a couple days now, driving down (on the highway only) the Check Engine flashs randomlly, sometimes even looks like the bumps makes it light up, will stay on for a solid few seconds, then off, then flash again.

Seems to stay on solid whenever you really put your foot on the gas. Whenever theres a good load on the engine. Let off, light turns off, driving along @ 55mph flashes randomlly?



Could it be a loose contact/connector for something since it seems that the bumps affect it?


When I get off the highway, it's off and never comes on, not even with the bigest bump.

Have you pulled codes? Or get a friend or someone to sit in the driver seat while you wiggle the wiring.

I don't have a codes reader. Not right now anyways... never bother getting one, never had a computer controled engine before 7 months ago...

But the light is never on parked.

Mine does that, it's my EGR sensor malfunctioning. IDK if that is the problem, but it could be it! ^_^

Ford Fuel Injection » How To Run a Self-Test Here is a link to instructions for getting any trouble codes without a code reader. The CEL does not have to be on for there to be trouble codes.
Might be worth doing.

my 95 bronco did the same thing going down the highway...inbewteen 55-65 the check engine light would come on until i slowed to about 45...do the self testvery easy to do...but in the test i found it easier to not do the slash marks...whatever works best for you though

My stang was doin that, was idle air control sensor . Best thing to do is self test like lazy k said