1993 Nissan 240SX cars feels like it wants to turn off when

It could be the mass air flow sensor, but it would have set a code in the computer turning on the check engine light. Have you checked for vacuum leaks, fuel pressure, and when was it last tuned up?

no engine light on, last tuned a few weeks ago: how could i check fuel pressure and vaccum leaks?

and it cannt be fuel pressure beacause it rans in the freeway but just feels like it wants to turn off

If the check engine light hasn't been on, I would recommend checking fuel pressure. It may be weak but still working.

what should the fuel pressure be for this car

43PSI with out vacuum / 34PSI with vacuum

i have taken it to a shop and been told its the mass air flow meter-does that sound right?

shop changed the temperature sensor only and now the car runs great

That will do it. The sensor tells the computer the temp and the computer determines how rich or lean to run the fuel mixture.

Glad you got it fixed. Let us know if you have other questions, and thanks for using 2carpros.com.

Joe