Cat Light Lit! Starting problems too!

[hibbsy18]

i have a 52plate 1.8, and the catalytic converter light has come on. when i'm driving along for the first ten mins its fine, but after that its a different car.

Before it came on it would accelerate at the slightest touch of the pedal! Now it judders in first an second, an i get no power at all till 3000 wen the other cam starts working.

Then crusing in fifth at 70-80 it will slow down an not maintain the speed unless my foot it on the floor!!

Also when starting up after its been sat for a while (overnight) it revs to 2000 then drops down to normal, then down to about 300rpm, back up to 2000 for a second. So it does this for 5-10mins until its warm then its ok!

Anyone have the slightest idea why?

I use redex regularly, and i changed my spark plugs cos i thought it was them, i cleaned the throttle body too.

HELP

cheers!!

[brifen]

Hi There,

I'm no expert but i'm sure someone with more expertise will be along soon with a better diagnosis but it sounds it is to do with airflow. Have you looked / changed the airfilter recently and if it is okay then you may need to get MAF sensor checked out. Any smoke? (Black/Blue/White)

Could try running the car with pipe not connected to MAF to see if it idles any better.

Bri.

[Duncan]

MAF sensor would certainly be the first thing to check out. A careful clean with Isopropyl Alcohol would be a starting point.

[hibbsy18]

cheers guys, it wont be the airfilter, i've got a cone on atm cos of cold weather and i only drive at night! also i had a chat with someone today and he said it could be the 3rd pot that is misfiring due to a broken injector. but i'm going to take it to vx this week an get it diagnosed. i just hope its not to expensive!! i'll keep u updated

[brifen]

Will be interesting to know the conclusion.

Keep us posted.

Bri.

[Duncan]

What made the person think it was the injector? Have you had them out to look at?

[hibbsy18]

well it pops and the engine is not idling properly. i havent yet taken them out, but i will be doing it tomorrow morning. it was snowing all day and was dark when it stopped. i took the throttle body off today and one of the holes was blocked, its only a 1.5mm hole. its the thin pipe that comes off the top of the cam cover. that didnt help.
however, wen its idling the butterfly is sucking in too much air and it flaps open and closed, could the motor in that be dying??

[JACKALG1]

ive got the same problem with the Cat light , where will i find the MAF sensor and can i get to it easily.

Thanks Guys

[Big Sig]

Follow the air pipe from the air filter. Its a large round thing with a multi plug on it. Can't miss it.

[rushy]

well it pops and the engine is not idling properly. i havent yet taken them out, but i will be doing it tomorrow morning. it was snowing all day and was dark when it stopped. i took the throttle body off today and one of the holes was blocked, its only a 1.5mm hole. its the thin pipe that comes off the top of the cam cover. that didnt help.
however, wen its idling the butterfly is sucking in too much air and it flaps open and closed, could the motor in that be dying??

Did you get it sorted? What was the problem, MAF, O2 sensor?