I own 1989 240 SW. I've been trying to get my arms around a problem of running rough, black smoke, and terrible mileage. (about 7 mpg).

I check the FI fault codes, and I did not realize that there could be more than one (as I learned). So I kept pushing the button and 3 separate codes came up in this order:

2-2-1: Fuel system compensating for extremely rich/extemely lean air/fuel mixture at cruise (FYI: this code is different from code 231 in that the word "extremely" is added)

1-1-3: Fault in fuel injector(s)

1-2-1: Fault in signal to/from mass air meter


In these same fault tables, the column that says "Check Engine Light ON", there is a YES. Can I assume that the blinking "Shift Up Arrow" can be construed as a de facto "check engine light"?

Again, I appreciate the help of the people who have responded in the past, and I greatly appreciate any opinions regarding this new info. Hopefully, with these 3 somewhat specific codes, a smarter person than I can deduce what
problem(s) I should deal with.

Thank you,

Alex

PS: After a week, at least it started up no problem.
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'73 164E/'76 240SW/80 240SW/89 240SW @315Kmiles!