Volvo: Engine trouble, mass air flow meter, mass air flow

Question
Hi,

I have a 1989 Volvo 740.  I was driving one day, when all of a sudden, the engine started sputtering.  Feels like it running on 2 cylinders.  It will idle ok, but as soon as I start to let the clutch out it stalls.  I brought it to a garage, they checked it out and seemed to think it was a problem with the engine wiring harness.   I have since replaced the harness (which was in very bad shape).  But the problem still exists.  All cylinders seem to be getting spark and fuel.  And I think that the garage pressure test, but I'm not certain.  Any insites you can provide me with would be greatly appreciated.


Thank you

Jason  

Answer
This sounds like a faulty sensor issue.  The computer takes reading from multiple sensors under the hood and uses that information to help keep the engine running in tune.  With your symptoms, I would suspect either the Mass Air Flow meter or the knock position sensor.  Have those checked out.  Good luck!