How do l get this as cheap as possible including install?Can l do it myself?

Details:
2002 Nissan Sentra
117,000 miles
Also have fuel fume leak around gas cap and need to replace auto lock function.

Should l just trade it in now before more starts to go wrong?

the mass airflow sensor works off of a closed system, & if their is an air leak in the system it will throw a code informing u the sensor is bad,first u need to make sure no air leaks r present or it is an improper code, this is what tells the computer on u vehicle to give ur fuel injection system to give the vehicle more fuel. the easiest way to check for a leak is to get a can of starting fluid & start ur engine, & then spraying the starting fluid at all the connections, if the engine revs up when u spray the starting fluid on it that is where the air leak is & u need to tighten up that connection, if the engine does not rev up then the chances r that ur mass air flow sensor is malfunctioning

Like what was said above..do u need a air flow sensor? Is the car running very poorly & wont rev over 3000rpm?

If it is the air flow then it is very easy to replace. One electrical connector & two clamps. l would think even for someone that has never wored on a car that it should not take more the 1/2 hour.

Why trade it in? These cars r good for 200,000 miles & 20 years.

You know the history of the car better then we do. If the car has had regular maintance then u will get another 10 years out of the car. You might spend a few hundred a year on it but it is cheaper then a car payment.

You cant and no. It is a common failure and the result of that failure is lack of power. But make sure there are no leaks first.

Auto lock try changing the battery in the remote first.

The gas caps fall apart so get it fixed rather than trade it in.Better the devil you know