95 chev Blazer OBD2.
The truck runs well, i don't detect any missfires.
Had checked at two auto Zones and no codes,
At idle no SES light, and i can rev the RPM's up and still no light.
Then when i back out of the driveway and go about quater of
a mile the SES light starts flashing and does not go off till
i shut off the engine. My question is, does the SES light flash
for another reason besides missfire? Thanks for any help you
can give me!

 

The only reason I have ever seen is for a misfire. If the SES light is on, a code should be stored. Some codes reset when the key is turned off. If you have not done so already, try to get to Autozone when the light is on and do not shut off the truck when you go in to get them to scan it.

 

Any reason the SES does not come on at idle and when i rev the RPM's up.
If it was a missfire wouldn't the car run ruff?

 

It all depends on engine load. Most misfires are under load. While increasing the RPMs while in park or neutral, there is very little load on the engine.

There are many things which can cause the PCM to think there is a potentially harmful misfire. A loose or grounding out knock sensor connection/wiring or a bad knock sensor may cause the PCM to register a misfire that actually is not occurring. Carbon buildup in the cylinders could result in hot spots which will cause detonation, registered as a "knock" and classified as a misfire as well. Problems with the ignition system resulting in either a lack of ignition in a particular cylinder or multiple cylinders will be read by the PCM as a misfire as well.


*EDIT* -

*Moving to 2nd Gen Tech*

 

I replaced the cpi spider and ran for about 200 miles, no problem.
Then i decided to replace the starter. As soon as itook the
first trip out of the driveway after putting on the starter, this is when
the SES light started Flashing. Could i have caused the problem putting
on the starter?

 

I personally have never heard of a starter making the SES light go array.. do what Swart said and go to Autozone when the light is on or even flashing, and let them check it then dont shut it off..

 

Thank you! That will be my next step!I will take to Auto Zone
and have it checked while the motor is running. Thanks again
for your help!