erratic idle problems

[bringles]

This seems to be a common problem. My head is spinning from all the possible things to check for. My check engine light is on. The code came back as 1221, oxygen sensor 1. I have heard many times that people replace it, but the problem continues.

Here are the details:
erratic idle (not all the time)
Check engine light is on, it came back as 1221
sluggish taking off
runs fine once the car is moving
gas mileage is fine, about 23 mpg in town
no smoke coming out of the exhaust
I notice a smell resembling gas or exhaust sometimes

Please help. Someone told me they solved this problem by replacing the cam position sensor and cat. I cant afford to replace a long list of parts hoping to solve the problem.

[Devildog90]

i have same problem i was told dme so i bought a new still have problem just bought o2 sensor so i will try that i hope you find fix. for i have same problem on my 92 318i.

[Hokori]

@ Bringles;


What type of Bmw is it? (model, engine and year).

Let's start simple first. Buy a can of carb-cleaner. Clean out the ICV.
Check around for vacuum leaks.
Check around for intake gasket leaks.


In theory, the oxygen sensor shouldn't be the problem for a rough idle when the car is just started (cold start). The DME has a baseline value for a cold start, when the engine warms up, *then* it takes the o2 sensor into account.

This is more or less from the manual, so if it's not correct, I'm not fire proof (as in, don't flame me)