fullymatted.
Back to search
Rennlist

996.2 Curious engine issue during warm up

Add to repair workspace
Open repair workspace
Original source
3 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW

Discussion summary

YOUR RESEARCH996.2 Curious engine issue during warm up

Leading reported evidence

Clean e-gas throttle body however

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

I have not yet cleaned the e-gas throttle body however, it looked pretty clean the other day when I had the air box off looking for vacuum leaks.

996.2 Curious engine issue during warm up
Read full discussion summary

Leading evidence: 'Clean e-gas throttle body however' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Clean e-gas throttle body however' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.

Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.

Read captured replies

1 matching discussions · 3 captured posts examined · 0 partial discussions

Compare 4 other evidence results

Test ok

Performed · outcome unconfirmed

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

The fuel vapor solenoid tested ok.

996.2 Curious engine issue during warm up

Clean other day

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I have not yet cleaned the e-gas throttle body however, it looked pretty clean the other day when I had the air box off looking for vacuum leaks.

996.2 Curious engine issue during warm up

Run more than a couple of seconds

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

If I park the car and leave it for about 1-2 hours then restart it whilst it is still warm from the earlier run, still completing the throttle body re-calibration, it will start fine, idle fine and then if I drive off after a few minutes with the engine temp at about 70 deg C, it will stall and for about 2 minutes refuse to fire and run for more than a couple of seconds.

996.2 Curious engine issue during warm up

Run of the day

Suggestion or failed attempt

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context

Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.

Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

Other than it happening on the second run of the day from warm, the only other common factor is that each time I have reversed it down my steep driveway out of the garage however I can't see how that could contribute.

996.2 Curious engine issue during warm up
Frequently discussed actions (8)

These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.

Clean e-gas throttle body however

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

I have not yet cleaned the e-gas throttle body however, it looked pretty clean the other day when I had the air box off looking for vacuum leaks.

996.2 Curious engine issue during warm up

Clean other day

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

I have not yet cleaned the e-gas throttle body however, it looked pretty clean the other day when I had the air box off looking for vacuum leaks.

996.2 Curious engine issue during warm up

Replace first though was

No successful repair reported for this finding.

0
Reported fixes
1
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that report an unsuccessful attempt
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Unsuccessful attempt · Original poster

The first though was that it was a crank angle sensor however that has been changed and it made no difference.

996.2 Curious engine issue during warm up

Replace with a known functioning unit

No successful repair reported for this finding.

0
Reported fixes
1
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that report an unsuccessful attempt
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Unsuccessful attempt · Original poster

Similarly the MAF was swapped with a known functioning unit and that also made no difference.

996.2 Curious engine issue during warm up

Run more than a couple of seconds

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

If I park the car and leave it for about 1-2 hours then restart it whilst it is still warm from the earlier run, still completing the throttle body re-calibration, it will start fine, idle fine and then if I drive off after a few minutes with the engine temp at about 70 deg C, it will stall and for about 2 minutes refuse to fire and run for more than a couple of seconds.

996.2 Curious engine issue during warm up

Run of the day

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

Other than it happening on the second run of the day from warm, the only other common factor is that each time I have reversed it down my steep driveway out of the garage however I can't see how that could contribute.

996.2 Curious engine issue during warm up

Run still completing the throttle body re-calibration

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that contain suggestions
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Suggestion · Original poster

If I park the car and leave it for about 1-2 hours then restart it whilst it is still warm from the earlier run, still completing the throttle body re-calibration, it will start fine, idle fine and then if I drive off after a few minutes with the engine temp at about 70 deg C, it will stall and for about 2 minutes refuse to fire and run for more than a couple of seconds.

996.2 Curious engine issue during warm up

Test ok

No successful repair reported for this finding.

0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Discussions that performed work without a confirmed outcome
1

0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.

0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.

Performed · outcome unconfirmed · Original poster

The fuel vapor solenoid tested ok.

996.2 Curious engine issue during warm up
Coverage and how to read this overview

Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.

3 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.

  • Rennlist: 1 discussions

0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.

0 acknowledgements have no verified action link; they do not establish a repair result.

Generation: 20261026T103553Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources

POST 1 / ORIGINAL POSTEROriginal post

Hello, I have a 2003 996 C2 that has a curious engine issue during warm up. Here is the problem, which I have been a been able to replicate on 3 occasions over the last couple of weeks. The location is Brisbane, Australia and its currently mid-summer. If I start the engine from cold and immediately prior to engine start, complete the throttle body re-calibration process, the engine starts, warms up perfectly and drives perfectly. If I park the car and leave it for about 1-2 hours then restart it whilst it is still warm from the earlier run, still completing the throttle body re-calibration, it will start fine, idle fine and then if I drive off after a few minutes with the engine temp at about 70 deg C, it will stall and for about 2 minutes refuse to fire and run for more than a couple of seconds. It usually takes 2-3 throttle body re-calibrations and 5 minutes before it starts and then runs perfectly for the next 30 - 90 minutes as though there was never a problem. I first noticed the issue 2 weeks ago when I started it cold and without doing the throttle body re-calibration as I didn't know about that then. On that occasion, at about 70 degrees, the idle started hunting between 1100 and 600 rpm. It would almost stall before the ECU would catch it and then back up to 1100 rpm until it would die, get caught and then back up to 1100rpm (repeat for a minute). My warm up procedure is quite systematized and curiously, the three times I've had is stall on the road, it has done it in nearly the exact same location about 700m from my house on flat ground. If it was a carburetored engine I'd say it was running out of fuel since it is a complete engine shut down, not just a cylinder or two like with an ignition issue. The first though was that it was a crank angle sensor however that has been changed and it made no difference. There was a code for a crank angle sensor which is what prompted the replacement. Similarly the MAF was swapped with a known functioning unit and that also made no difference. I have also checked and confirmed that the fuel vapor solenoid valve near the alternator is functioning when I trigger it with a 9v battery. There are no obvious vacuum leaks I can see. Other than it happening on the second run of the day from warm, the only other common factor is that each time I have reversed it down my steep driveway out of the garage however I can't see how that could contribute. It does it equally with a full tank of fuel and nearly on reserve. It does it will the ac unit running or not. My current thoughts are that it may occur at the same time the engine switches from open loop to closed loop during engine warm up, however, without knowing the timing for that during the warm up ecu map its hard to say. I'm tending to think that if not fuel/ignition mapping related, it may be another ecu controlled function that is triggered during warm up, for instance the other vacuum solenoid that sits near the alternator with the outlet that disappears under the inlet manifold towards the air oil separator. I have not yet cleaned the e-gas throttle body however, it looked pretty clean the other day when I had the air box off looking for vacuum leaks. Interestingly, when my mechanic changed the crank position sensor last week as a result of a logged CAS code, it threw the same code upon start up. That's when they also tried the other MAF sensor. Incidentally, the starter works fine. Any thoughts and suggestions would be appreciated. The winning correct suggestion that fixes the issue, will receive 1000 good karma credits from both the universe and me.

POST 2Original post

The fuel Vapor solenoid may be sticking open. remove the hose and see if it is pulling vacuum with the electrical connector off.

POST 3 / ORIGINAL POSTEROriginal post

Thanks dgmark. The fuel vapor solenoid tested ok. I took the car back to the mechanic last week and it had logged a code for left bank cam sensor. That was subsequently replaced and (touch wood) it has been perfect since. Odd that the sensor had behaved in the same way on three separate occasions but I'm happy to let it be.

This is a source reference. Confirm exact model applicability in the original material.