I have sentra 160 DOHC,when driving and I want brake,revs come down and car stalls?

First eliminate all vacuum or air leaks in the system. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

Thanks,how do I replace IAC?

Do the other stuff first and then worry about that.

Hi,did what you told me to do,still the same...what now?

There are no specific instructions for changing the IAC. It's held in by a couple bolts.

Thank you,it worked......now there's a new problem fuel consumption seems to be a lot,idling is at 2000 rpms,is this normal,I changed the fuel filter,the carburator is okay......

Look for vacuum leaks

Okay thanks,I know it's a vacuum leak,but where do I start?

My car has had an overheating problem for little bit, it was not anything major at first. Every now and then the temperature gauge would spike for a little then drop back down. After a week or so a rev limiter would kick in at 2000 rpm's. If I pulled over and let the car sit for a few minutes it would be okay for little while then it would do it again. I replaced the radiator cap and thermostat. Also, when using a code reader it came up as a bad thermostat but even after replacing it it still does it and the temperature gauge stays hot for a longer time before randomly dropping.