Over Labor Day weekend, I took a drive up to Mt Evans in Colorado. The elavation at the top is over 14,000 feet. On the way up. around 11,000 feet my 2001 996 C2 started cutting out. It was like the ignition was turned off. This would happen for about 2-3 seconds and then turn back on. It did this 5-6 times and I thought I should turn around. It still did it 4-5 more times on the way down the mountain. I didn't have it checked out because it stopped cutting out until yesterday. I was just driving around and it started doing it again. The exact same thing . . . it's like the engine was turned off for 2-3 seconds. I don't get a CEL or any notification of any problem. It only seems to do this under light load when I'm just cruising around. Do you have any idea what can be causing this? I've got 3 track days this weekend and I don't want any engine problems. Thanks a lot.

Ken

 

An MAF sensor or bad fuel.

 

Probably not bad gas. The cutting out happened over a month apart from each other. I did get a CEL about 2 months ago. This was before the cutting out problem. I forgot the codes but it was something to do with the oxygen sensors. I sprayed my MAF with MAF cleaner, unplugged the battery and haven't seen a CEL since. This is my 2nd MAF. The first one was replaced about 2 years ago. I'll have to check with Sunset Porsche to see how much a MAF is. Thanks for you reply.

Ken

 

How in the world could bad fuel do this?

 

Wrong octane number.

 

It was cutting out again yesterday. I've got a 2.5 hour drive down to LaJunta, CO for a track weekend. It seems to only do this after driving for around for 45 minutes. I've talked to two dealers who have no idea what can be causing this . . . especially with no CEL.

I really paid attention when it was cutting out. The radio and air conditioning stayed on, power steering worked, so the car still had power. When I pushed the accelerator, nothing happened . . . then three seconds later, like a switch was tuned on, the car would go again. This is very strange.

I'm going to clean my MAF, unplug the battery to reset everything, put a can of BG 44K fuel injector cleaner in and a full tank of the best gas. This one station I go to has race gas(no lead). Maybe I'll put a little in to get the octane above the crappy 91 in Colorado.

Wish me luck.

Ken

 

How is your ignition switch? Loose or sloppy? Hook up a scanner and log your MAF and load figures. See what happens to them when the power fails.

 

I've never noticed. I'll wiggle it around and see how it feels. I don't think it's changed in the 4 years I've owned the car . . . but you never know. The dealer suggested if it happens again, go soewhere without turing the car off and have the codes read. Even tho there isn't a CEL, there may still be a code that will tell us something. He thought turing the car off might be resetting this code and that's why nothing is showing up. Thanks for the suggestion. This is so strange.

Ken

 

Try depressing the clutch, or shifting into neutral when it happens. This will tell you if the engine is shut down, or maybe a problem with the accelerator pedel. Careful though, if engine shuts down completely you will loose power steering, and after a bit, vacuum, so no power assist to brakes.
Of course letting off the clutch will turn engine over again and get you steering and brakes.

 

I have a tip. But that's a good idea. If it does it again, I'll shift into neutral and see where the rpm's go. If they drop to zero and I'm going 60 mph, is it o.k. to put it back into drive. I guess I could just leave it in neutral and see if the engine fires back up after 3 seconds like it has been doing. Thanks for the help.

Ken

 

Not sure if the Porsche has a Throttle Position Sensor but I had the EXACT same carachteristics in one of my BMW's last month. I did recently throw a maf and an o2 code because the cutting out was very similar to what you are descibing as well. I raplaced the MAF and go trid of the K&N filter and have ahd no issues or codes since. My .02.

 

That would be a first.