I recommissioned my 993 varioram in April after it's winter storage and have had a misfire since starting using in May, what I've done to rectify is outlined below and the current issue is that having just replaced the MAF the car now starts fine and appears to have no misfire (great that seems solved) but the car has a 80% chance of stalling at junctions once I depress clutch. I have read that the ECU takes time to remap to a new MAF, is this correct and how long should I expect this to take (miles / engine on time?)?
Timeline
Oct 22 - Put in garage after 993 event to Northway Porsche
Winter - cleaned various engine ancillaries (which I think also included MAF plastic and maybe damaged MAF sensor?)
June - Full service including spark plug change at Tognola who suggested ignition leads may need replacing
June - Almost emptied tank and half filled with Exxon 99 Supreme (still misfire)
June - Replaced ignition leads, then dizzys and rotors and then coil (still misfire)
July - Tested air intake temp (has ohms in range)
July - Replaced MAF with OE Match replacement from Design 911 (misfire has gone and idles ok when cold but once warmed revs drop too low and stall occurs)
I have rationalised that if MAF was reading high (less air going in engine than the MAF was measuring), then ECU was putting in too much fuel and hence the occasional misfire and pop bang in exhaust that ECU was trying to adjust for. Now a new MAF has gone in (correctly reading) the ECU thinks its getting more air than it actually is and hence running out of oxygen for combustion and stalling). Not sure if my synopsis is correct so looking for guidance....thanks. Will ECU recalibrate and how long will it take/can I reset to factory? I don't have an OBD reader.
Timeline
Oct 22 - Put in garage after 993 event to Northway Porsche
Winter - cleaned various engine ancillaries (which I think also included MAF plastic and maybe damaged MAF sensor?)
June - Full service including spark plug change at Tognola who suggested ignition leads may need replacing
June - Almost emptied tank and half filled with Exxon 99 Supreme (still misfire)
June - Replaced ignition leads, then dizzys and rotors and then coil (still misfire)
July - Tested air intake temp (has ohms in range)
July - Replaced MAF with OE Match replacement from Design 911 (misfire has gone and idles ok when cold but once warmed revs drop too low and stall occurs)
I have rationalised that if MAF was reading high (less air going in engine than the MAF was measuring), then ECU was putting in too much fuel and hence the occasional misfire and pop bang in exhaust that ECU was trying to adjust for. Now a new MAF has gone in (correctly reading) the ECU thinks its getting more air than it actually is and hence running out of oxygen for combustion and stalling). Not sure if my synopsis is correct so looking for guidance....thanks. Will ECU recalibrate and how long will it take/can I reset to factory? I don't have an OBD reader.