car judders when going at a steady speed at around 2k rpm

[jason1987]

as my cats nackered, and i thought thats the symptoms of a worn cat

[Mikeemikester]

Either I'm now paranoid or my exhaust is sounding like it has a slight 'blow' now too.

[craigtd]

Mine is doing the same thing!!! Mine is the 2.0l Petrol on an 'S' plate. Would mine have a lambda sensor being non turbo?

Cheers guys, Mike.

yes it will have a lambda sensor, it will be in the down pipe from the manifold to the cat, it looks a bit like a spark plug.

[jason1987]

got new car fitted but it still does it, dunno what it could be?, seems to do it when im on overrun aswell, so makes me think its not spark plug related? or would it still do it?

[TRAVIS BICKLE]

mine did that, how many miles has yours done?
Loads of things can cause this, throttle position sensor, air intake temp sensor, vacuum leaks, boost leaks, coil pack breaking down, plug leads, breather problems etc etc
But anyway mine was something on the throttle body, I changed the engine but swapped the inlet manifolds over. Still had this problem. swapped the throttle body over with one that had done 70K miles less and now its as smooth silk on part throttle and cruising.
I remember the nissans i used to work on had very similar problems with worn throttle position sensors.

[jason1987]

120k, it only seems to be when im just over 2k revs for some reason, or thats when i noticed it, why only certain revs? and even when your off the throttle and coasting?

also it randomly lags/boggs, sometimes it will feel fine and sometimes ill put foot down and turbo will suddenly kick in and feel different

[TRAVIS BICKLE]

Boost control system? Throttle position sensors do wear out and become dirty / damaged / worn where the throttle pedal spends most of its time ie around about those revs. it sounds like you may have a couple of different faults there? do you have a boost gauge, you would see any boost spikes / dips then.

[jason1987]

na not got a boost gauge, is usually when the engines warm as in been driving it a while, and also seemed onced id booted it a bit the turbo went back to normal and kicked in, strange, maybe a cheap air filter. so cleaning throttle body might help the judder problem?

[TRAVIS BICKLE]

its worth cleaning it all out, i cleaned mine before fitting, you will need a new gasket though. you can take the sensors out of the throttle body and clean them if your careful, but if the tracks worn on the TPS replacement is the only option there.
you could go round all the pipework with some carb cleaner round all the pipework joints etc, if the revs pick up or it stutters you may have found one problem.

[jason1987]

wonder if the dump valve is causing it?

[TRAVIS BICKLE]

just take the vacuum off the dumpvalve and take it for a drive. see if its any better.