Hey guys I noticed the other night on my way home that my engine light started flashig, my truck seems to be running perfectly normal but as soon as it gets around the 45 mph it will flash a few time but if it shifts gears or i let off the gas it will go away.
. Any help i have no idea what it could be!?

 

You'll have to run a self-test to get the codes, which should help to figure out what your problem may be: Fuel Injection Technical Library » How To Run a Self-Test

Depending on the year of your truck, you'll either have two digit or three digit codes. 87-91 are two digit: Fuel Injection Technical Library » 2 Digit Self-test Codes 11-32

92-96 are three digit: Fuel Injection Technical Library » 3 Digit Self-test Codes 111-171

 

If the check engine light is flashing, that is BAD. That means the ECM has detected a problem with the engine that can cause damage to emmissions components (catalytic converter). As Bob stated, you need to find out what code(s) are setting to begin diagnostics.