My 1997 55sx has failed the MOT on both 1st and 2cnd fast idle test.


CO% are 0.00 and 0.02

HC ppm are 8 and 10

Lambda is 1.05 on both tests.

The garage fitted a new lambda sensor with no change. From the readings I assume the cat is ok.

Any ideas what to do next?

hi, stick tank of optimax in, bottle of fuel injector cleaner, bottle of cat cleaner and then go and thrash the **** out of it, i mean like revving it right upto 5.5k and flooring it, down your private lands's motor way upto 80-90

should do it

well thats cheap way lol

yeah bottle of cleaner is wortha go and also make sue you giv it a godo thrashing before the test get engine nice and hot

Have put some cleaner stuff in the tank and taken it for a run.

It certainly runs smoother and starts better.

Also compared my car with another one and the heater on mine blows much cooler air. Removed thermostat and its stuck partly open so have got a replacement which I will fit over the weekend.

New test on Monday.

Sounds like it wasn't upto temp. What temp was it at when the tests were carried out? It should be printed on along with the other levels.

Just says oil temp was 80C, don't know if that is normal or not.