ok so i drive a 91 civic si and when i start the car it runs fine for about 5-6 minutes and then it just shuts off. I've taken both my battery and alternator to advanced auto parts and auto zone. they both said the same thing. both parts were fine. so can anyone help me out with this please?

 

how is the air filter( is it clean) and how does it idle when you are stopped?

 

You ever thought it may be a problem with the choke? It normally takes 5-10mins for the motor to get up to running temps which is when the auto-choke shuts off. If the mixture is wrong or throttle not opening wide enough it'll keep stalling.