db9 misfire data question

[pcn1]

I'm reading a lot about the potential dangers of the engine misfire, changing of the plugs and coils and how the technicians can detect a misfire with their software.
Is that detection in real time only, or does the car keep historical data of misfires that can be read?

Theory being if a car has a history of misfire over a longer period of time, then inspection of the cats would be wise before any purchase?

Thanks

[AstonKeeper]

I don't believe it holds misfire data after the battery has been disconnected. AMDS can do it live though. A software inspection during a pre purchase inspections is an option, but popping the cats off for inspection would be a little involved. I do remove all the wheels, plug in and do a several mile road test during a PPI, Aston's standard 140 point check plus my own extra points!

Aston Keeper

[LTP]

Not trying to add to the paranoia (the risk is real, but so is the risk of being struck by lightning - do we all wear rubber boots and hat at all times?) but Aston1936 has a video showing how to check the cats in situ by taking out the O2 sensors and using an endoscope

[Simpo Two]

pcn1 said:

I'm reading a lot about the potential dangers of the engine misfire, changing of the plugs and coils and how the technicians can detect a misfire with their software.
Is that detection in real time only, or does the car keep historical data of misfires that can be read?

In theory, both. However misfires frequently don't record a code, so the best answer is to do live data and follow the driving sequence. I'm having mine checked soon.

[CatalystV12V]

Another way to check for misfire is to do a full throttle acceleration from 47mph, in top gear. This puts maximum load on the coils and you (apparently) will feel it shudder. .. I was told this a few weeks ago by a local independent.