1997 Silverado at 65 rpms stay high and check engine flashes.

you have a misfire condition, do a tune up to correct it and all should be good

No mention of misfire, rpms is the key word, #1 if it is at all possible to run at 65 rpm reason the check engine light would be coming on from low oil pressure. Again if this motor can run at 6500 rpm, which I do not think so because of the Rev limiter, could be low oil level in the engine.

Now on my 1995 Silverado , I put a chip in the computer to change the Rev limiters rpm. I can run 8000 rpm with my motor.

Rowefast there was no mention of misfires. the only thing to make a engine light flash, that's why I was going that route, Low oil pressure would make the oil light come on not so much the engine light. just my take on this, the question is lacking in information, Im taking it at 65 mph, with high RPMs. Sometimes very hard to diagnose over the internet.

I was not the one talking about a misfire, Were in his question does he mention a misfire?

The check engine light flashing indicates misfires, the question is very poorly worded and punctuation can change what he means by simply inserting a comma. Everybody calm down, lol.