Help - Jumpy Idle and Stall in Warm / Hot Weather

Hi Folks,

Warm spring weather is finally here and my 2003 330i ZHP with 39,000 miles has developed an idle issue that seems only exclusive to warm / hot climate. I'll jump straight to the point.

Problem:
- Car occasionally exhibits jumpy idle...dipping from 750 rpm down to 620 rpm (digital readout) to the point of almost stalling but manages to recover
- However, there have been instances when the car does not recover from the dip and stalls (sometimes at the worst time during traffic).

A few things to know:
- Appears that initial engine start up (cold engine) and driving in warm weather does not exhibit idle problems. Only following start ups from a hot engine exhibits idle issues.
- Cleaned my MAF, ICV, TB, and DISA valve a few weeks ago
- Car does NOT have cold idle or start issue nor exhibits any of these idle problems during cold weather (below 50 F)
- No codes or lights
- No cracks/tears in boots
- Always run 91 octane

Potential Solution:
- DME update. I've read that some have solved their idle issues with this.
- Replace camshaft intake Sensor
- Replace Vanos seals
- Run fuel cleaner & replace fuel filter


Thoughts / inputs?

DME update is a possibility, although I thought that was more valid for the 3-4K rpm dead spot.

I wouldn't throw money at the CPS just yet.

I haven't seen or heard of many cases where the Vanos seals were bad enough at 39K to result in stalling, however replacing the seals is never a bad idea since it will have to be done anyway and is a fairly cheap DIY.

Not convinced about the fuel filter being the problem.

Did the problem start before or after you cleaned the DISA? Was the DISA clicking at all?

That's some low miles for an 03. I would check for vacuum leaks and seals that have dried out from not being driven enough. Maybe just a valve cover gasket or intake boot. That e30 bmw stuff mainly but I think it still applies.

The problem occurred before the DISA clean.

Interesting you mentioned VCG because I'm convinced my VCG are leaking because of the burn oil smell after a spirited drive. Could valve cover gasket leak cause the stalling problem?

DISA rudder had resistance and did spring back into place. Yes, clicking as well.

Major leaks at the valve cover gasket can cause oil fouled spark plugs as well.

Thanks for the suggestion..I will pull the plugs and check.

If you are pulling them you might as well get new platinum 4's.

SES light? Codes?

Clean the Idle control valve....and inspect the disa, when you replace the lower intake boot. Oops...yop pretty much did all that huh?

May also wanna do plugs...dpending on when you did them last.