emissions trouble, help!!!

[craig c]

hi all having a tad of trouble, took the car for an mot failed on emissions.
the garage said you need a new cat and lambda sensor,so all fitted went back for a re-test and surprise
its still the same .
plus whilst testing the car was left running and just stopped and wouldn't start for another 10 mins,

co level was 1.733 fast idle
                   
                   2.068 second fat idle

                   and 8.153 natural idol

they said it seems to be getting to much fuel,any ideas would be appreciated

[Rhyso]

What engine?

[james2]

i would check the engine over ,look for any boost leaks and a new set of ngk platinum spark plugs.

[craig c]

What engine?

sorry 1.8 agu non turbo

[jamie16v]

i would say it could be te lambda sensor... have you taken or has it been taken out before?..

[craig c]

i would say it could be te lambda sensor... have you taken or has it been taken out before?..

that was replaced same time as the cat all new today, and the car seems to judder a bit at low speeds but if you give it some its fine

[jamie16v]

what brand of sensor was it?..
also has it been scanned for codes? it could be a number of different sensors. try unplugging the maf and see if it runs any smoother. second choice would be a dodgy CTS..

[craig c]

not sure what make the lambda is, tried the maf and it ran more lumpy, as it was running crap at low speeds befoe the cat etc was done, I would presume what ever is causing this  is affecting  the emissions to be off the scale,
they did scan it ,cleared it and took it for a spin they then said try a crank sensor,would this cause the
emissions to be so high

[jamie16v]

if the crank sensor was faulty I doubt it would run as the ecu wouldn't know when to fuel or spark.

[craig c]

sorry for being blonde but what is the cts?