I own a ST202 Celica (Jap Import) & live in the UK & my car has just failed an emissions test.
I have been told that the problem could be with the Oxygen Sensor,has anyone out there had this problem as these are quite expensive & I don't want to buy one & find out that it is something else.
I have been quoted about £140 from a Toyota Dealer.

Thanks in advance guy's >>

when was the last time you changed your oil?

The oil is changed every 4000 miles.

you could try taking the O2 sensor out and cleaning it.

Before I go in for Emissions testing, I get the oil changed and drive the car around for an hour or two. My mechanic told me that helps a little.

yea that does but do check your O2 sensor. just whip it with a clean cloth.