Volvo Repair: My 89 240 dl wont run, mass sensor, air mass

Question
I have a 89 240 dl that runs fine during
the winter or when its cool weather,but during
the summer it sputters and stumbles ,it just
wont go.I have changed wires sparkplugs
distributor,injectors and gas.I cant get it
over 20mph.What do I do?

Answer
My guess is a bad air mass sensor. Testing doesn't help. You need to replace with known good one to verify, and use an original volvo unit. and if this does cure the problem, be sure to replace the temp sensor inside the air cleaner box also.
This repair can be expensive, so I would have some shop do a thorough diagnostics before condemming the air mass.