Temporary DME amnesia?

[Steve87-911]

Mysterious rough cold start idle

My 87 has run perfectly in the time I've owned it. Always starts and runs smoothly. (I keep it tuned/maintained). I normally drive it twice a week, about 100 miles round trip each time. But, it did sit for the past week and a half and when I started it today it idled and ran like it had a couple fouled plugs or that the timing suddenly was whacked...real rough. I pulled a couple plug wires one at a time and noticed no diff. Hmmm.
Prior to initial cranking I did press the gas pedal down and let go to set the choke-like thing. (Sorry, I don't know the name of the device that does the choke-like/cold-start-assist functions on motronics.)

I was about to start troubleshooting but thought I'd drive her slowly to see if she ran like crap when warm. But, she suddenly started normally and ran great even while still cold. I took a fun run and she runs perfectly again and starts fine now.

So my questions are:

1. Can the DME ECM suddenly lose its mind (map) even if there were no loss of battery power?

2. What is the name of the device that performs the choke-like function on 3.2s when you press and release the gas pedal? I'm suspecting that may have been involved, unless my 3-yr old ECM just had a "senior moment".

Thanks in advance!

[ewave]

1) There is no battery backed memory in the 84-89 DME's. Disconnecting power would have no effect on the way the part operates, or powers back up.

2) There is NO mechanical choke on the 84-89 Carerras. It is ALL electronic. The DME monitors the temperature of the engine, and if it detects a cold temperature, in richens the fuel air mixture by increasing the pulse length to the injectors.

No need to pump the gas pedal, or even press it slightly when starting a Carrera, hot or cold.

[Steve87-911]

Originally posted by ewave
...No need to pump the gas pedal, or even press it slightly when starting a Carrera, hot or cold.

Thanks Paul, that's what I read too. Still, when it's really cold, if I step on and off the gas one time before cranking, it starts and idles nicely immediately, where if I don't, it hunts for a few seconds before settling down. And this was the situation before today's weirdness so it's not today's problem.

The reason I thought that the DME ECM could suddenly lose its mind was based on what I read in Bentley on pg 240-4. The note there says that poor driveability could result if the battery had been disconnected previously (mine wasn't) because the DME adaptive memory is erased and that after 10 min of driving it re-adapts. So now I'm confused. Is Bentley wrong?

[ewave]

The adaptability is true for the 1990 and newer 911s.
If Bentley is referring to the 84-89 Carerra's, it's wrong