1500-2000 RPM judder
'05 GT JTDm developed a nasty judder on Friday night. At approx 1500-2000 RPM 5th/6th gear, whole car judders horribly. Judder subsides when you lift off the throttle, and appears to be less severe at high revs. No judder if you drop the clutch and rev the engine in the the same rev band.
117000 on the clock (mostly motorway miles), standard unmodified car, no remap or similar.
I took the car in to Autolusso on Saturday, unfortunately it drove well on the way there. However they quickly found play in steering control arms, replaced these, performed a 4 wheel alignment and replaced a tyre. It drove well on the way home.
Later in the day I found that unfortunately the judder is still present. It seems like it's more severe when the engine is up to temperature, which would explain why AL didn't find anything else.
I'm reading around and there seem to be a large number of things that could explain the judder, here's my through process:
CV joints: there's no click or knock on cornering.
DMF: no judder on idle, no vibration or weird feeling through the clutch, no whine. Problem is intermittent -seems unlikely that a DMF fault would be intermittent
Driveshafts: I assume Autolusso would have spotted any play on Satuday's inspection.
Buckled wheels or lost wheel weight: would almost certainly still judder when I lift off the throttle
Engine mounts: no problem whatsoever if I rev the engine in the same band with clutch disengaged
EGR: I'd never have assumed EGR, but I've seen dicussion threads for VW TDI models with similar threads point to the EGR. I've had EGR faults in the past and the problem I had was very sluggish, smokey take-off.
I'm keen to explore anything I can before I take it back in, so any advice where to start would be great... especailly anything that is likely to rule out the DMF...
Partly blocked injector: Dicky's suggestion below
Last edited by LiamGT; 29-04-12 at 21:59.