When I turn on the left blinker it blinks fast I changed out the bulb and it still does it but when I turn the right side it works fine and even when I put the hazards it works fine

SOURCE: Chevy Cavalier 2001 turn signal blinks fast

If new bulbs don't work, it is probably the harness that holds the bulb. I had to replace both on my car after fighting with the problem for over a year and not knowing.

SOURCE: right blinker does not blink

With the vehicle In Park and the ignition on, swith the R/S signal on. Now , gwt out of the car and walk to back of car and inspect the R?R signal light . OK ? Now, do the same to the R?F signal light. One of them are not going to working correctly. Replace the defective bulb, or socket

SOURCE: left rear turn signal light on my 1999 chev. s10 is not working

any increase in bink speed is direcly related to a bulb being burt out.

SOURCE: Blinker blinks fast, replaced bulb, it burned out too

Most cars have separate flashers for each side now, and in fact, if it still blinks, even though faster than normal, there's probably a short circuit somewhere on the light wire where it's exposed and making contact with the frame of your car or some other metal part, which then causes the bulb to burn out.

SOURCE: left blinker blinks faster than the right. which

Flasher relays relies on bulb wattage for the speed of the blink.
You probably just have a blown bulb in the left rear blinker.:)