I have a 2000 nissan sentra with about 200k miles on it. It has never had any major problems until recently. when i start my engine after it has cooled down completely the engine will run fine for a few seconds then the rpms will drop slowly and then the car vibrates some then quits. could it be the maf sensor? i can't figure it out

Probably way overdue for a service, take it to a properly qualified and licensed mechanic you know and trust.

Hi Kate,sounds like your valves need adjusting,here's a link on how to do it.Here's how you remove the valve cover.

Open your hood and see if the vacuum hose from your power brakes has come loose,it goes to the intake manifold.

Sounds like you have a major misfire problem. The light is flashing because the ecm has determined that the problem is severe enough to cause damage to something. If your engine light flashes it is a warning not to drive the vehicle. I'm assuming this is a four cylinder. My guess would be that only two of the cylinders are actually producing any power. I would need the following details to help you further. How many miles are on this engine? Has the necessary factory maintenance schedule been maintained? In other words have the appropriate parts been changed and serviced to keep this engine performing properly. Many things could be causing your issues. Do the necessary maintenance first, like spark plugs and whatever the manufacturer requires and see what happens. If this does not help I can help you with the rest.

the nissan sentra has a timing chain which should last the entire life of the car and should not require changing

Do you have access to the vehicle? We will try some things.

may be your throtle assembly. seen some failures with those.

First of all have you done obd2 scan test for codes?

ITS just run in you silly person as the normal engine (the heart of the car) will do about 200,000 miles and still go strong ...But you dont have to drive like a mad man just look after it and it will serve you well ..

There was a recall on the Crank Angle Sensor and another recall in which the engine would consume too much oil due to faulty piston rings