A first for my M, this morning a CE light! Looking for ideas..

[JETninja]

Started her up as I was headed to work....little lumpy (does that if I've not driven in days...so that was weird) and I notice the CE light on. I kill it, restart and its still on.....I open the hood, nothing obvious or new noises...even checked the gas cap. So I drove, and the first stop the idle is all over the place...I keep giving it a little gas thinking it may die.

I'm think now, instead of heading directly to work I'd hit up the shop....its still rough after another stop or two, but then a minute or two later (10min total since I left home) the light goes out and the idle is normal at stops. I drive the 35m to work with no issues.

3:30pm and I'm ready to go home, starts up fine and no issues, so I stop by the shop to pull codes.

Something activated the "Knock Sensors"....

Cleared the codes and drove home.

Any ideas? Its less then 1200m from 200K...Vanos is a tad noisey but the car runs great. Just passed smog last month.

Never once had a CE light up....only thing different is the previous 3 days I ran the AC every day, morning and afternoon. (its been in the 90s hear in SoCal, even 7:30am its been high 70's and muggy)

Maybe she's getting nervous, I'm planning on adding a C5 Z06 very soon, and she'll be parked outside. Ha Ha...

Weird Stuff!

[dano670]

Maybe you got some water in the gas tank. Water settles to the bottom of a tank and maybe it got picked up in the fuel system. I think rubbing alcohol lets the water be absorbed into the gas. I forgot the chemistry term for it. Not miscible.

[JETninja]

Hmmm...interesting idea. Not sure how though, I only run Shell, and no rain in quite awhile. I do 70m every M-F, so I do run a lot of gas through it...

Warner Robin's eh? We deal with the USAF there daily....was there on business back in the early 90's...

[dano670]

Warner Robin's eh? We deal with the USAF there daily....was there on business back in the early 90's...

Yeah, I was active duty AF for a few years here and now I am civilian. It pays the bills. The base has grown a lot.

[khaos]

ICV maybe? Mine does that ALL the time in winter, figured it's the ICV. Weird that it does it hot though.

[sharpie1k]

The ICV could just be clogged or gummed up. I would check it out.

[JETninja]

It only did it that one time, been fine since. Over 500m and no hiccups.

[LuxoM3]

Voltage Regulator?

When that thing starts going it trips all sorts of weird codes - but KS the most.

My theory is when the VR starts dying, the CE not only flips, but the spark charge is also screwed up.

You still on the original Alternator/Voltage Regulator?

I haven't seen the KS or CE light or sputter since I dropped in my the new Alternator/VR back at 150k... at 197k now.