My wife was driving our 1996 850R, with 150k, the other day when it started running very rough so we had it towed home. On investigation yesterday the car would start idle fine for a minute or two and then spit and sputter til dead unless I gave it gas which would cause lots of black smoke(very rich).Checked all vacuum line. and connections finding none at fault even the one running under the intake manifold which I replaced last summer. I have observed something lately I never noticed before, constant idle speed motor humms for about a minute after I shut the car off. I never noticed this with any of my 700 or 200 series cars. I removed the idle speed motor and it actuates fine when twisted quickly. Pulled three plugs and they are black from running full rich. I like fixing my own cars, can't afford the dealer, so I went and bought a 70.00 dollar Actron scanner. It gave me three codes two of which there is no iformation for. Code PO103(MAF or VAF A circuit high input) Code P1505(no information and Code P1507(no information) I looked at some information and found a code PO505(Idle control system malfuntion and code PO507 Idle rpm higher than expected. These code could be from some of the playing I did yesterday when I disconected the Idle Air Control vavle when the car was running. I cleared the codes with the scanner and started the car it still runs the same but the codes did not come back. I would greatly appriciate any ideas.
Thanks,Tom
Owner 91 780, 89 740T, 62 P1800, 79 242GT(soon to be turbo) and lastly my 850R(frustrated front wheel driver)