bob semp

Sorry shakenfake, there is no misfire, no stumble, no physical change in how the beast is running, no engine codes, just that stupid blinking light coming on for a while, then off for a while, then back on for a while when I run at highway speeds.

Yes Jsdirt, therein lies the problem. I have a code scanner and there is NO CODE being thrown or stored. That is the wierd thing. The truck runs great, with no hint of a problem, so I'm at a loss as to what is happening.

Yes Jsdirt, therein lies the problem. I have a code scanner and there is NO CODE being thrown or stored. That is the wierd thing. The truck runs great, with no hint of a problem, so I'm at a loss as to what is happening.

My 2002 Silverado 2500HD with the 6.0l Vortec consistently will throw a blinking check engine light when on the highway going a sustained 65 - 70mph. There are no engine codes being thrown, either as history or during the event. The is no other physical indication of what is happening - no roughness, no slowdown, no noise - nothing at all to tell me what is going on. It only throws the blinking light in that scenario - never during around-the-town driving. So far, I have cleaned the MAF sensor and replaced the Air Filter. Truck has ~ 120,000 miles. Apparently it is not "serious", as my son (who had the truck before me) said it was doing that the entire time he owned it lol. Anybody have similar issues, and know what might be causing it? Thanks in advance.