That could be a bad thing, make sure to check the manufacturer on that. I mean if such a well known company like Bosch is bad for our cars, then i'm pretty sure an off the wall company is definitely not a good thing. I'm not really sure hor or even if you can order an AC Delco one from the UK. But i'm pretty sure you can. Do you have any GM dealers in your area? You can probably get one there.

Depends. Most generic aftermarket O2 sensors just don't like the 3800. GM has a parts website, www.gmpartsdirect.com for your 02 sensor. I believe in leaving GM o2 sensors in the 3800, thats when they get maximum performance, and the very best gas mileage.

But yes, the computer also has to relearn the information, so disconnect the battery, key on, leave it for 10 minutes, drain the ECM of any stored memory. Plug the battery in, and take it for a drive, it shoud work well after a while.

I don't think GMPD ships internationally.

It could take a couple hundred miles for the ECM to re-learn the new sensor after you re-set it.
If it still runs like crap the sensor is defective, someone probably dropped it in shipping.
Migilla guerilla maybe.

If the O2 sensor you bought is a problem, someone here can pick up an AC Delco sensor and ship it directly to you. We've done overseas shipping like this for Members in the past.