starting problem
 

my car is having problems starting it does it randomly but more often if i drive it for 20 min or less i have a turbo timmer and it reads 11.5 to 12 volts before running then 14 while running. I have had the battery tested twice and it always checks out. I dont think there is a problem with my alternator but not sure. i know its a stupid question and probly a simple problem but any help would be nice.

So, is it cranking and not starting, or not cranking? It may simply be your starter failing if it doesn't crank sometimes, and works normally other times. Pretty common.

no it cranks everytime just week soetimes i just replaced the starter like 5 month ago

11.5 is very low for a fully charged good battery when the car is off. Start looking for parasitic drain....

Amp, Radar detector, parking lights, etc....

Swap batteries with someone for a couple days.

i do have an amp for my stereo. is the only way to check is switch batteries with somone. the battery varies fom 11.5 and 12.5 and its random

Not only way, but quickly answer if it is battery or not.

A good battery under very small parasitic load should be near if not over 13 volts.

Put an amp meter in-line with the car off and see what the draw is.

Pull ALL the fuses on any add-ons.

Take a volt meter and check the voltage between the positive and the side of the battery, and check all round each side, and the top. if you get a reading of over .1 anywhere (excluding the negative terminal(s)), take the battery out and clean it off really good (Carefully) you don't want to get extra water inside of it , or dirt, etc.

Also check your water levels, only top off with distilled water.

My old battery had a reading of like 4 Volts from the positive to the side, i cleaned it off really good and got it down to .06 or something like that. :)