Volvo: 86 240 Lunging, Stalling, mass air flow, maf sensor

Question
Hi Jimmy:  I have an 86 Volvo 240, Manual.  For the last few weeks it has had an intermittent problem where it begins to lose power, and then either lunges or stalls.  It appears to do this in lower-gears.  I had it checked out by a mechanic who could only recreate the problem once and has been unable to diagnose it.  

The mechanic replaced the primary fuel-pump (which did not help), and said the MAS airflow sensor would not be causing the problem because if it was the MAS it would not be drivable at all.  Also, the mechanic supposedly checked the fuel lines as well.

It does not seem to have anything to do with how much gas is in the tank - nor how cold the car is.  

I am at a loss for what to do next ... any thoughts on what the problem might be?

Thanks for you help.  

Answer
Hello Shannon! There are a number of things that can cause that problem. However, I would check the in-tank fuel pump first. Make sure it is working properly. The problem can be caused by a bad MAF sensor(mass air flow)or an O2 sensor. I would check the tank pump first. Let me know what happens. I'll be here to help!


Jimmy