Hi Team,

I am new around here I have a 99, c2 with an intermittent stalling issue! This could be a long post, I want to post a lot of detail to increase chances we resolve this also to help users in the future who might have the same issue.

I have poured over countless threads and absorbed the combined wisdom of this and other forums. I have taken the first steps to diagnose the issue and look forward to tapping into the expertise of this forum to inform my next steps.

The car's behavior is best described as "stalling whilst braking when coming to a stop" the conditions which are most likely to see this behavior exhibited "longer drives of duration 40+ minutes with traffic and or hills" meaning the engine is hot and working - only once has the stall occurred within a few kms of setting off without being stuck in a lot of traffic.The car will start right back up.

The threads I have read indicate the issue could be

1. Fuel pump - I have put a gauge on it and see 3Bar/40PSI, wisdom from this and other forums indicate this is low I should be seeing 55psi - if I accelerate hard the fuel pressure will increase. When I park the car, the fuel pressure will increase then come back down when the car is running.

• Do you guys think I should throw a new fuel pump in it?
• Do you have any alternate suggestion to trouble shoot?
• Do you think a failing pump would put out a lower pressure or it's likely not the pump?

Mine being a 99 has an inline fuel filter - replacing this has not impacted the fuel pressure. In case anyone is wondering the filter is located in the center of the car, in the
I have also checked the electrical connectors below the battery which connect to the fuel sender without opening up the fuel sender.

2. Crankshaft position sensor - A few threads are resolved with this sensor. I'm planning on replacing this - if we decide the pump should be replaced it'll happen at the same time.

3. Dirty throttle body - I'm told the AOS is bad on the car so I think the throttle body would be dirty I'm planning to clean this also.

and to a lesser extent as far as I've read the problem could be:

4. ICV
5. MAF
6. 02 Sensor
7. Corroded wiring (more related to hot, slow or no crank no start)

I'll worry about 4,5,6 and 7 later - keen to make a call on how to address low fuel pressure first.

Thanks!
Wyn

 

My money is on the ICV. Remove the throttle body and take the ICV off. I bet its sticking. Inspect it. I haven't been able to bring one back to life.
Idle Control Valve: 996-606-160-01
Gasket: 996-110-310-50

 

I've had these symptoms twice over the years on my 996. First one was solved a few years ago by getting a new battery. Yeah, I know. Didn't make sense to me either, especially as the battery tested within an acceptable range and was only registering maybe slightly lower than normal operation range on the dash voltage gauge. There are numerous accounts of these cars being sensitive to battery condition and manifesting all kinds of odd behaviors when a battery is outside of optimal conditions, but not bad per se. I first noticed problems once the car was driven long enough to get warm. I had read that the ground strap or some Y cable (PITA) can go bad and cause similar issues, but mine didnt have obvious corrosion so I gave a new battery a shot. If you go the battery route, get one with high cold cranking amps, 800 or higher IIRC.

About a month ago it was happening again, but this time in addition to the stalling when coming to a stop I was getting some weird behavior on full throttle. The car would occasionally sound like it was hitting a rev limiter (or similar to a launch control rev restriction) at steep throttle angles. This was occasional at first, but got really bad over a week. It never occurred until the car was fully up to operating temp. Finally got a CEL and code that indicated it was the crank position sensor. CPS was an easy swap and problem solved.

Ive had a gunky throttle body in the past, but that never manifested in idling problems. I've had stumbling/inconsistent/low idle issues that weren't accompanied by stalling and I ended up needing a new MAF. But I replaced the MAF early, so stalling could have been an issue eventually had I not.

 

The idle control valve is a likely culprit, along with a gunked up throttle body. I'd do as LAPorsche Guy said above and purchase a new ICV and gasket and give the throttle body a thorough clean and I think you'll have the best chance of fixing this.