Z4 Roadster (E85) Oddball engine issue

I picked up a 2006 Z4 M back in May with 55k on it....definitely the best car I've owned, love the power, the steering, the suspension...all of it.

However, it's done something twice now that has me a bit spooked.

Basically, I'll be driving down the road, normal highway speed, and shift down to pass, etc, and I get a service engine light, and it starts running TERRIBLY. I mean, like no power, feels like three cylinders. Exhaust note goes punky, everything. First time it happened, I thought, oh crap, there goes my VANOS....so, I pull off the road, get out, listen to it, see if I've got disconnected plug wires, etc. Can't find anything, so I turn it of. A few minutes later, start it up, and presto, no issues at all.

Now, the first time this happened, I was at 12,000 feet on a road trip through the CO rockies....chalked it up to maybe some issue with the altitude and air/fuel mix.

But, same thing happened to me last night driving home from work...and just as before, I pulled off, turned it off, started it up, runs like a top.

I'm stumped....any thoughts?

Originally Posted by meltonj72

I picked up a 2006 Z4 M back in May with 55k on it....definitely the best car I've owned, love the power, the steering, the suspension...all of it.

However, it's done something twice now that has me a bit spooked.

Basically, I'll be driving down the road, normal highway speed, and shift down to pass, etc, and I get a service engine light, and it starts running TERRIBLY. I mean, like no power, feels like three cylinders. Exhaust note goes punky, everything. First time it happened, I thought, oh crap, there goes my VANOS....so, I pull off the road, get out, listen to it, see if I've got disconnected plug wires, etc. Can't find anything, so I turn it of. A few minutes later, start it up, and presto, no issues at all.

Now, the first time this happened, I was at 12,000 feet on a road trip through the CO rockies....chalked it up to maybe some issue with the altitude and air/fuel mix.

But, same thing happened to me last night driving home from work...and just as before, I pulled off, turned it off, started it up, runs like a top.

I'm stumped....any thoughts?

Has the weather/humidity been wet? maybe some water/condensation in the gas tank? Try dumping some "dry gas" in there.

check for codes. gently tap on MAF sensoe with the car is idling....if it changes replace it. with it missing you should have at least a history code

Pull your codes. They will tell you what is going on. Good luck .

agreed, pull the codes, I'd say it's likely the camshaft position sensor.

Check for loose vanos bolts. If they break it is bad news.

The CEL is always emissions related. I'm going with the cam position sensor or possibly an O2 sensor.