Iffy Cat Maybe ?

[mikej]

2001 petrol 2.3, Any body replaced a cat due to running issues, had this car over 5yrs now but over the past few months it's lost it's go and appears to be flat as hell , revs fine but doesn't seem to shift up the gears like it use to, it will still happily plod along at speed but is taking time to reach it. Anyhow i have noticed if i rev it in neutral it revs nice and crisp but as the revs drop it appears to misfire on it's way back to tickover also once or twice it has felt like it was running on 2 cylinders and almost cut out but only for a few seconds , once on a steep hill clime and once on a hill descent. Had an issue last week after driving 250 miles on the motorway at approx 85, left on a downward slip road and hard breaking the car starting missing like hell again and almost cut out? I have smacked the cat with my hand and cannot hear anything loose in there, disconnected the maf and it certainly doesn't like that so if anyone can advise on how best to check it without disconnecting it as it's rusted solid or any other experiences of the same sort please share it ta.

The car is serviced to the hilt & has all new ignition parts etc so i know it's nothing like that

thanks again

mike....

[cyborg]

hi there,

If you've replaced coils plugs etc,

Then its likley before you changed those bits that the unburnt fuel cleaned off oil resadue from combustion chamber.Which in turn has killed the cat .

 

Had a 2.3 in summer which failed its emissions, I was in a rush so replaced cat and lamda sensor made a massive diffence to power.When I inspected the cat it was choked and a wonder the car ran at all .However In saying all that I would change the Lambda sensor first then let it tickover for 1/2 hour then go test it.

Edited December 17, 2010 by cyborg