I have 89 Lebaron GT turbo, 2.2 t1. On the way home under say mid throttle it would bog, stumble and pretty bad black smoke would come out of exhaust. Almost like a turbo diesel, it was pretty bad. Also when i would stop for a stop light the idle would go down to about 500 rpm and run pretty rough for a few seconds then rebound back to normal. If i floored the excelerater full boost would come on and things seemed pretty normal and the smoke wouldnt be there. No check engine light came on during all this. When i got home i cycled the key and only came up with two codes, 12 and 51. Just fininshed installing a rack and pinion so had the bat. disconnected so that covers the code 12. If i read rite code 51 is a lean situation. Any ideas? And if it was lean how come all the dark smoke? Doesnt that indicate a rich situation? Where should i start?