Engine stutter on startup...

[Porschekid]

Almost without fail it seems on my first startup of the day I will get an engine stutter and the idle drops really close to stalling. It starts right up with no problem, idles fine for about 5 or 10 seconds and then the idle drops almost to the point of stalling and then corrects itself and is fine from then on out. This seems like the only problem the engine ever has. I don't know if the computer is running some test that it is having a problem with or something. Anyone ever experience this before?

[VTvaster]

Is the AC on when this happens??

Mine will do that but only when the AC is on during start up.

It could be the engine is not warmed up enough and with the AC on, you are asking a little too much too soon.

I have experience this in other car as well, that is why I bring it up.

Also how many miles/year?

[Porschekid]

2000 2.7 with ~50k miles... as far as I know A/C isn't on.

[clubhead]

Originally Posted by Porschekid

Almost without fail it seems on my first startup of the day I will get an engine stutter and the idle drops really close to stalling. ...

This is a typical sign of MAF (Mass Air Flow) sensor failure. Go to a independant specialist or Porsche center to have your DME fault code read. It should point to that.

You can either clean it wth carb cleaner or replace it for about $250. What year's your car?

If it's using a 996 606 124 00, that is superseded by 986 606 125 00 or 986 606 125 01. Upgrading to a later model MAF will require a DME programming which your dealer should be aware of. If you're using a 996 606 123 00, you're pretty much stuch with that. 996 606 123 00 is meant for non EGas cars though..

My aircon's always on and that never presents a problem on cold start.

[Porschekid]

Should there be any other signs of MAF failure? That seems to be my only symptom and it's only on the first cold start.

Are you running good gas? 93 octane? Have you tried a high quality fuel cleaner with Techron?

[Porschekid]

Originally Posted by bmussatti

Are you running good gas? 93 octane? Have you tried a high quality fuel cleaner with Techron?

Always 93 or 94... It's only really a weekend car though if that makes a difference. I got Chevron Techron at home but haven't put it in yet because I wasn't sure if it was safe in these cars. I will put it in if you think it won't cause a problem. I also don't have a CEL. I used to think it was because I was putting the top down and it was putting too much drain on the battery but it does it even if i'm not putting it down.

Originally Posted by Porschekid

Always 93 or 94... It's only really a weekend car though if that makes a difference. I got Chevron Techron at home but haven't put it in yet because I wasn't sure if it was safe in these cars. I will put it in if you think it won't cause a problem. I also don't have a CEL.

I have used 2 of the Techron fuel cleaners already. One at about 200 miles and another one at about 5,000 miles.

Make sure it is concentrated enough for 17 gallons of gas. The small ones are only good for 12 gallons.

It may help. And it may require more than one treatment. And it may be something else completely. Sorry.

Porschekid, your comment about being "a weekend car" got me thinking about the following question that was recently asked on the PCA website:


"Question:

My average fuel economy has been approxiately 16 miles per gallon on a mixed loop.
The vehicle is driven seldom because I am retired with nowhere to go, except to the store.
Is this normal? It had its 30,000 mile inspection 2 years ago with no problems found.


Answer:

This seems low even for city driving.One thing to keep in mind though is how old is the gas? Gas that sits in a tank for more than 30 days without a stabilant will go bad. When a fuel starts to break down it will loose its combustion characteristics and not be as efficient.
You could have the car checked by a shop with a tester to make sure the MAF (Mass Air Flow) is not in a full rich mode. These will tend to either go bad or get a film on the sensor plate causing this. They could also check the O2 sensors to make sure they are operating properly at the same time.
One last item to check is for leaves and debris in the air filter housing. You will have to remove the air filter and make sure there is NO debris in it. Leaves and other items tend to fall in when the filter is removed. The filter is replaced and these items now are trapped inside the housing and obstruct the MAF.

Scott Slauson - PCA WebSite - 8/21/2006"





So, how is your gas mileage? Could be stale gas??

[Porschekid]

Thanks, that is something to look at. I don't monitor my mileage closely because I use it so infrequently. I may try to rack up some miles and get it as close to empty as possible and then put in a new full tank of 94 and add the Techron to it. I wasn't aware that gas broke down so quickly... After sitting for almost a complete Winter it still seemed to run well enough on the gas that was in it but maybe I wasn't paying enough attention.

Did you stabilize the fuel prior to winter storage?

If you want great winter storage tips, do an advance search with key words "winter storage" and search by user name "MNBoxster". You will find some great stuff.

I think you should add the Techron ASAP and fill up the tank. And then refill the tank again ASAP. You need a good 300-400 mile road trip ASAP!!

Porschekid, is your car running better? Did the Techron & fresh gas resolve your problem.