Occasional Stalling

[suburban99]

Had my 1997 Boxster 5 speed on the road for about a week or so now. Cold starts good. Idles ok when cold. After driving for 10 minutes or so, sometimes it will stall when I come to a traffic light. It did this about 5 days ago, then it was good for 3-4 days, now it did it again this AM. Car cannot find its idle....sometimes. I have cleaned the MAF, and idle control valve and throttle body about 2 months ago... No CEL present but have had PO1126 and PO1124 about 2 weeks ago. I occasionally check the codes even if the light is not on...I suspect MAF is going south but need another opinion before I spend $300 or so.

[qikqbn]

hey suburban99...

hmmm.. could be several things.... don't know how mechanically inclined you are but here are some suggestions to consider...

1. clean MAF sensor.... I use 90% rubbing alcohol... poor into cup, then "dip and swirl" the MAF sensor

into it a few times... shake and let dry for a few minutes...

after re-installing, unplug battery for a few minutes to reset computer... MAKE SURE YOU HAVE RADIO CODE...

2. While the sensor is drying off.... remove air intake tube and give throttle body a good cleaning with some

carburator cleaner or thottle cleaner... watch out for over spay into eyes!

3. New Air Filter??

4. Check tension on throttle cable... cables can stretch over time... a little trick to increase rpm idle and throttle

response is to add a "zip tie" to the very end of the cable where the "hammer anchor" at the very end of the cable slides into

throttle control hook.. ... its like adding a little spacer in there to take out some slack.. just enough to take

out some tension.... not too much or your idle will be too high... I had to play around with it a bit to get it just right..

... think of it this way too... if cables are stretched enough then full pedal fully pressed is only opening throttle body 90% versus 100%

see here for a little more insight

http://www.renntech.org/forums/index.php?showtopic=4446

5.. Fuel or gasoline treatment to clean injectors...

6. New spark plugs

7. better fuel.... are you using cheap gas, low octane??

those a few things I would try first... if all else fails I am sure the dealer would not mind

taking your money ;^(

Hope these work instead of dealer... all the best.

Bill

Edited May 1, 2009 by qikqbn

[Glyn]

I think the fault is with your idle speed control unit, either the solenoid activator has failed or there is still gum in the slidy flap inside the control body, take it off again and ensure the flap retracts easilly.

Secondly check for air leaks - either around the idle speed control valve itself or the pipework, sounds as though air is being sucked in somewhere, Is the idle steady when strting from very cold or does it fluctuate? If no fluctuation then youve ruled out the air leak.

Any difference when air con is on?

[suburban99]

Thanks for the replies guys. I will re-clean the MAF again. I did not disconnect the battery last time but car was laid up as I was repairing the Varia Cam and timing. I think I had the battery disconnected but can't remember. Car idles excellently most of the time. I will recheck the idle control valve as well, as the gasket was questionable.... I have a new air filter coming from Sunset. Idle is steady when cold. Throttle body is clean.

[JeTexas]

The car will run a pre-mapped program without the MAF, so if you unplug it and it stops stalling out, then you know it's the MAF.

If you've already cleaned the throttle body and Idle Control Valve, my next guess is clogged injectors.

By the way, you can order the Idle Control Valves through Autozone, and they have a very lenient return policy, so you could always swap it out to check and then take it back if that's not what you need.