Code P0128, Have i tried everything?

[redskytattoo]

Hello, my name is Jim and this is my first post here after lurking for a couple of years.

I own a 2006 X3 and about a year ago my check engine light came on.
i got a code P0128, which is the thermostat or temp sensors.
My impression was that there were 3 things it could be:

-thermostat
-temp sensor near front of car
-temp sensor under the intake manifold

I have done all three myself and its taken quite a lot of research and work to do, and yet still, between 40-150 miles the light comes back on and reads the same code.
I can't get the car inspected here in New York with the check engine light and am pulling my hair out trying to figure this out with only a few days left in my extension.

The inside temp gauge seems to be working properly and coming up to temperature as it should.

Is it possible there are any other solutions to my problem?
Anything else i could check?
Does a BMW dealers shop have certain diagnostic equipment that i don't have?
Should i just give in and bring it in just for a diagnosis?

I'm currently out of work and am really trying to fix this myself, but i feel like I've hit a wall! and i don't want to pull off that damn intake manifold again!!! Any help would be greatly appreciated.

Thanks,

Jim

[glader60]

It's good that you were able to replace the parts yourself, though just throwing parts at a problem hoping to resolve is not diagnosing.
Get the proper OBD II cable, install INPA or ISTA+ on a laptop and diagnose from there. Just search for INPA or ISTA.

[jclausen]

What quality parts are you using and you are clearing the fault correctly. Shops and dealers have tools that you and I will never have