My new used 1993 240 classic wagon is trying to humble me. It has numerous issues and when I fix one, another crops up. First, the headlights would not dim. I replaced dimmer relay and cleaned terminals on light relay. Then,dimmer worked, but the formerly properly working turn signals went crazy. Turn signals work, ( sort of ), with lights off, but only left one with lights on.

Car would idle rough, sometimes dying at intersections. Replaced throttle body with a cleaned 89 throttle body. Now idles smooth, but a day later check engine light is on and car acts like it has a fuel, or ignition problem. It has not stranded me, but it surges and acts intermittently like it is fuel starved.
Any ideas?