Start/idling issues
 

My '78 911SC that has recentyl been re-awakened from a year or so nap, is hard to start. After several attempts and stalls, she idles very rough. Once started she stumbles a lot as I try to get going. Once warm, she runs fairly well with no problem running thru the gears and getting to speed. However, once she cools off, the problems re-occur. The Clymer shop manual mentions idle mixture and/or idle speed adjustments but I'm not sure how to proceed. Advice from the experienced? Thanks.

There are lots of possibilities here.

What was the condition of the engine before you put it to bed? Any start problems then? Make sure all ignition components are up to spec.

Was gas stabilizer used? If not, then you should probably get fresh gas in there. You MAY be able to top it up w/ new and be OK. Or you may have to drain what you had and start fresh. You should probably change the fuel filter too. You could have water in the fuel, so a deicer might help. Draining and a fresh fill is probably best.

Depending on where you live and where it was stored, you may have some CIS component issues, due to condensation. Check that the WUR is operating correctly and that the screen on the top @ the fuel line isn't clogged. Checking the fuel and control pressures w/ a gauge will tell you if the fuel distributor is OK and the WUR is functioning correctly. Make sure the AAV is helping to raise the sensor @ start and the AAR is keeping the idle speed up during warmup.

Make sure there are no vacuum leaks. When the car sits idle, things like hoses can deteriorate, and clamps and screws can loosen.

Make sure the air sensor plate is able to move freely w/ no sticking or binding.

Was there any smoke? Oil can leak down into the cylinders over time. Sometimes you just have to get the revs up for a while to blow it out.

Check your plugs to make sure there is no fouling.

If the engine and FI were in good shape before the nap, you shouldn't be too long in getting it up to scratch. Good luck.