Hey guys I have 2004 Chevrolet blazer ls
recently I replaced spark plugs, spark plug wires, distributor cap and rotor. But when I step on the gas about 5000rpm my check engine starts flashing you know what might be the problem?

 

Running it to 5000 RPM too many times? Seriously though, the flashing CEL is supposed to indicate a misfire. check codes. Do you feel any misfire?

 

How is it miss fire I replaced the spark plugs
and spark plug wires and the distributor cap and rotor

 

Correct, Flashing Check Engine Light means Class A Misfire - one that is happening right as the light is flashing.

The best thing to do is usually to shut the engine off ASAP and let it coast in N to somewhere, the engine can only withstand so much of that.

"How?" Am not sure. But go very light on the throttle or turn it off when it's doing that or it may be bad...

 

Just because the parts you replaced are new doesn't mean they aren't defective. What brand did you use? Everything you mentioned should have been AC Delco for best results. Also go back and check your work. Installation errors can happen to anyone mo matter your level of expertise. We're all human.
But definitely do not continue to drive like that. It will cause major damage if you do. Good luck and keep us posted.

 

High RPM misfires could be caused by carbon buildup in the cylinders & on the valves causing hot spot which in turn cause detonation. It is also possible that you are running a really poor grade fuel and increasing to the next higher octane fuel would "cure" the problem. You could also try running a fuel system cleaner through a few tanks (something like Chevron Techron) which would serve to clean out some of that carbon as well. Seafoam or GM Upper Engine Cleaner are also options for cleaning the valves & combustion chambers.

Spark is only one part of a multi-part equation to get proper combustion. The other parts are fuel, air (and compression of it), and proper timing of it all. Misfires can occur if any one part of that equation is off as well as if there are external factors at work (hot spots causing detonation, etc).