Ok i originally had problems with car where it would not rev which ended up being a stuffed blocked up cat.
Now it is sometimes not all when you nail it it runs crap but if you hold it it clears at around 5000rpm and pushes hard.
Other than that you nail it then off then on off till it actually runs right through clean.
It has new and tested leads,coil pack checked out to be ok, plugs new,
filters new, cat new, pacey comp new, changed over fuel pump from another vehicle, changed ecu, all sensors check out to be good.

My next step is to take off exhaust after cat to see it there is a problem with the rest of the exhaust weather blocked from old cat insides or loose baffels.
Just don't want to get caught buy the boys in blue for excess noise and don't want to falk out for a new exhaust if not needed.
May need to go to a test and tune at willowbank so i can find out.

Any other idea's to the fix would be great.

What about clean throttle body and/or idle speed controller?

have a back pressure test done on the exhaust. it saves taking it off.

The throttle body is clean as a whistle and Idle speed sensor looks like new.
Idle speed sensor should only cause idle problems.
Thanks for reply Timmeh.

Who does exhaust back pressure testing and what sort of dollars do they charge?
Thanks for reply Tickford_6

Driving back from work yesterday I drove close to center barriers and it is sounding like it is coming from center muffler.
I am going to pull centre section off on Tuesday and give it a good shake and see if any old cat internals come out or if there sounds like there is any loose baffeling inside.

HOw the hell do you take off the idle speed controller? That's the thing we had a thread about, right? The plug at the front of the engine.

that was the crank angle sensor till_lind...

the idle speed controller is on the throttle body, near where your intake joins.