Was thinking of one more thing for you to consider.
You say runs very rough and lean - 'fumes burn your eyes !'
You say the car kind of stutters until you get on highway and than runs well. Higher rpms can can mask a single non firing cylinder.
Not good if this is unburnt fuel coursing out through the exhaust. Risk of ignition in a hot catalytic converted if you have incomplete firing/ignition of spark plug(s).
You can do a simple test of the 'spark' at home without have to drive it to your mechanic and risk having unburnt fuel in the exhaust system. See the attached link for the how to and purchase an inexpensive little tester to do it.
Things that can cause lack of spark to a single cylinder are a bad spark plug, a bad ignition cable, a degraded ignition rotor. I doubt it is a bad ignition coil cable for you would have 4 cylinders down and would run terribly even on the highway, which you said it didn't. Exclude this as a cause before you drive it to your mechanic. If this test is good and you have spark on all cylinders then look to MAS or LH computer.
https://www.youtube.com/watch?v=9Vl9JlIFiic