Well, replaced the cam sensor tonight, and the crank sensor 2 weeks ago and the car seems to be running better but there is still the lack of performance and an overly load induction/exhaust noise. I paperclipped it when it started playing up but only the cam sensor showed 0340.

I've done a plug and lead change, and checked the breathers and all are clean n clear. The problem only seemed to turn up when the cam sensor started playing up but I cant think what has gone wrong, unless the ecu hasnt sorted itself out yet after the new sensor was fitted.

What are the symptoms of a knackered cat or lamda sensor? Should I get a code for both of these? Car is a 2.0 16v 1998 manual with aircon

When idling, if you blip the throttle there is a huge hesitation before it revs but if you do it smoothly it revs ok. When driving it seems to be producing a lot of noise and not a lot of go, certainly less than usual.

Its had new crank and cam sensors in the last couple of weeks but I thought it would purr after these were done but I think I might have other issues.

Help please! 

I was kind of thinking along those lines but the car is 80,000 miles old and I thought the cat might have given up, it looks pretty rough from under the car but I didnt check the back box.

Better go and give it a shake.

No rattles from the cat so i'm thinking its something more serious.

The engine is pinking like mad under load and when I open the airbox and take the filter out while its running the engine is making a rythmical popping sound as apposed to the usuall induction suck.

Does this sound like a stuck valve and would this have caused the cam sensor fault to show up? what does the cam sensor do?

Really need some suggestions here cos i'm running out of ideas and its the missus kiddy carrier so we are stuck without it.

Please help!

150k and on original cats still plenty of life in em hopefully

Cats on their way out normally smell like rotten eggs when wamring up - but brake fluid  makes loads of smoke and makes an engine pink..

Sounds like you might have a valve problem, though...could be as simple as a lazy tappet, or an actual sticky valve

i'll record it with my camera tomorrow and post what it sounds like.

I hope nothing major.