I've been having a weird problem w/ my 1990 245. While it seems to be running pretty well most of the time,sometimes when standing at idle, I'll lose RPMs and car will start chugging and try to stall. Checked codes ,which showed "AMM signal missing." and "problem w/ injector"well ,I checked resistance of AMM, and sho'nuff, too many rrrrrrrrrrrs. Replaced AMM with seemingly good used one(based on resistance values), and while I was at it, since I had a brand new fuel pressure reg. replaced that too, and ext. fuel filter.Things seemed all better for a while, but same , rather infrequent but annoying and disconcerting problem emerged.Could it be fuel flow.int. fuel filt. or pump? Stalling out at any given intersection in D.C. area could be really, really bayyad, mmmkay.this problem is so intermitant it's hard to pinpoint. thanks for any ideas.