dmwalsh10

I am a new owner of a 1999 911. I've had the car since august 2017. But, did not drive it all winter (New York state), due to a coolant system leak. I fixed the leak (new expansion tank installed.
I followed the documented process to bleed the cooling system and all was great. Car was running great for two days. The it seemed to stall just a short distance from home and I was able to coast into my driveway.
Now when I start it, it revs over and over from 500 to 2000 rpm's and it want to shut down and struggles to keep running. I thought I had ran out of gas when it shut down and maybe I did. But when I added gas it still rev's up and down over and over.
I did put about 2 gallons of 87 octane into tank to get it too a gas station before trying to start it. same rev occurred. Then I added 5 gallons of 93 and still the same issue. The when I opened the engine compartment i noticed the coolant was below the min line.
I added about 1 quart and still the engine start is the same...

Any help is much appreciated

Dave in Saratoga NY

Porschetech3

Sounds like you caused a large vacuum leak as you were changing the coolant tank. Check the oil fill tube for cracks, and the oil cap for proper sealing.

sjg1138

Yes, sounds like a vacuum leak or sticky idle control valve (ICV). My advice is to clean the ICV and replace ALL of the vacuum lines and be done with it. The stock lines/plastic fittings are garbage.