760 turbo wagon

Thanks in advance for the assist. I have a 760 turbo wagon that my
teenage son drives. All of a sudden, extremely poor performance. Limped
to the local mechanic, was told that the air mass meter was bad ($650)
.. I did some research and found a good used one. It behaves exactly the
same as with the original. That is, no start unless the amm connector
is unhooked. I don't know what direction to go in. Did my mechanic
maybe disconnect something else also? I'm getting confused. I hope
someone can help me. Thanks,Dave

 

Did you get the right AMM? There's several different ones, they look
pretty much identical but have different numbers.

What year is the car? Pre-'89 will need a new engine wiring harness by
now, it will never be dependable on the original harness.