Engine Stalling On Takeoff

[schmidter91]

I purchased my 1982 Porsche 911SC about three months ago, and have put 1000 miles on it. Since I got it, I've noticed some problems with the idling, and some issues when taking off.

Idling: Occasionally (once about every 250-350 miles) the idle will fluctuate between 1500 and 100 rpms. It will never die, but it will come very close.

Takeoff: Sometimes (once every 20-50 miles) when I'm starting out (foot on accelerator, 1500rpms, clutch slowly being let out) the engine revs will drop to about 100 rpms, but the engine will catch itself and the revs will come back up to normal. There seems to be no bucking or hesitation, the revs just drop, but the engine catches itself.

Tonight was very humid and rainy. When pulling up to a stop sign, I pushed the clutch in and heard a pop as if the gear shift lever had been popped out of third to neutral, the dash lights lit up as if it'd been killed, but then promptly went off as the engine caught itself and continued to run as normal. Also tonight, starting off, the revs dropped and the dash lights came on again as if it'd been killed, but then sprang back to life.

I looked in the maintenance records, and a fluctuating idle issue had been reported, but not to this extent. Before we purchased the car, it had been sitting for about a year only driven 150 miles or so. It is almost time for 10,000 mile tune up. Any ideas? Fuel pump, fuel filter, oxygen sensor?

[stlrj]

It might be running rich.

[914efi]

Only choice is to go through system checks, control pressures, etc. One thing easy to do yourself is checking for obvious vacuum leaks.

[BURN-BROS]

Originally Posted by 914efi

Only choice is to go through system checks, control pressures, etc. One thing easy to do yourself is checking for obvious vacuum leaks.

And check for a worn out dizzy!

[Paulporsche]

I think a tuneup is in order. I'd pay special attention to ignition items, incl cap, rotor, WIRES, CDI and coil; all those other items mentioned, too.

And, you can either try Souk's field test for CO because you might be set a little rich, which does seem to manifest itself more on hot, humid/rainy days. or have it set by someone w/ an analyzer, just to be sure. JW recommends 3.5%.