Question about Cat Lamba sensors

[cleo]

Hi, I have had issues with my exhaust system, being really verbal an shaking, I was told it was the CAT an I needed it sorted so I just paid around £250 for a new cat, anyway the problem soon came back after around 2 days but I sine been told it could be the cat's lamba sensor by a diff place, now would the cat I paid approx £250 for have included the sensors? (THink it has 2 right?) And if it was my sensors that are causing it, would my onboard computer tell me so?
Thakns

 

[Dan@SJM]

NO, and possibly, mine ddint show any lights when my lambda sensirs were fucked,

what are the emmissions?

 

[cleo]

Hi Dan,
I have the result of a mot I had (an passed) in April (I had the same issue then)
Fast Idle Test
Engine speed: 2500-3000
CO: 0.15
HC: 38
y: 1.004

Natural
CO:0.14

I been told as long as it passes the emissions to not worry, but it makes from a uncomfy ride, an you can hear the blubbing from a good 10 yards away lol.

 

[Dan@SJM]

doesnt sound like lambda sensors tbh, sounds more like a plug breaking down/fuelling issue, when were the plugs last changed?

 

[cleo]

Hi Dan,
I changed my plugs about 3 months ago in an attempt to fix it, also changed the HT leads for some red ones from k-tec an even changed the coil pack, but non really made any difference.

 

[Dan@SJM]

Running it on super? or regular unleaded?

it sounds from what you've said that its missfiring every so often, hence making it judder etc.

What mods are you running?

 

[cleo]

I run it on BP ultamate or V-power depends where I am, only mod is the ht leads, an a filter (ITG?)

 

[mark989]

good explanation fault finding here. very usefull!!

http://www.picotech.com/auto/lambda_sensor.html