Good evening all,

I'm hoping someone can shed light on a problem I can't get to the bottom of.

The symptoms are:

When I take my foot off the accelerator, there is a pause and then the car lurches momentarily. Occasionally it will lurch a couple of times. The lurching is particularly noticeable when the engine is not up to temperature and is about 80% better when the engine is up to temperature. The lurching is worse when using engine braking when going down hill. It can really kangaroo a bit.

The second symptom (again, much worse when the engine is cold) is that the car seems to hunt when going along steadily between 1,400 and 1,800 revs. I can hold the accelerator at a point where it will just be on-off-on-off.

It has been on diagnostics at a Landy specialist. No fault codes. The car has had an EGR blank, straight through pipe and a remap by Mike at Dynachip. I don't know if it didn't do this before. I have replaced the harness and rtv'd the loom's weak points, cleaned the red plug several times and then put vaseline in the port to prevent further ingress. She starts up instantly, accelerates smoothly, without fault, and pulls like a train. The problem is only when neither accelerating nor decelerating at low revs, and when decelerating. Always much worse when cold.

Please throw all the suggestions at me that you can!

Many thanks👍
 
It's an EU3 (15P) manual.
Unplug the MAF sensor and see how it runs that way... if it runs well a new MAF is needed but only the genuine LR is reliable which is frigging expensive so better without it than with a cheap aftermarket which can mix up things... to avoid a guessing game the straight way to the problem is a live data log to catch the inputs while the symptom occurs... this should have been done by that so called "Landy specialist" when no fault codes were recorded cos as long as there are readings and it's not a complete sensor failure there can be fault code free while the management might be mixed up by an erratic input for fuelling
 
Unplug the MAF sensor and see how it runs that way... if it runs well a new MAF is needed but only the genuine LR is reliable which is frigging expensive so better without it than with a cheap aftermarket which can mix up things... to avoid a guessing game the straight way to the problem is a live data log to catch the inputs while the symptom occurs... this should have been done by that so called "Landy specialist" when no fault codes were recorded cos as long as there are readings and it's not a complete sensor failure there can be fault code free while the management might be mixed up by an erratic input for fuelling
Thanks Sierrafery. I'm sure I've tried unplugging the MAF before, to no avail, but I'll try it again. The Landy guy suggested that the wastegate control valve/solenoid might be the cause. Does this sound feasible?
 
Thanks Sierrafery. I'm sure I've tried unplugging the MAF before, to no avail, but I'll try it again. The Landy guy suggested that the wastegate control valve/solenoid might be the cause. Does this sound feasible?
No, that would have other symptom like overboost, it would affect acceleration above 2500rpm, find other real specialist who knows how to diagnose a Td5, as i said live inputs are necessary
 

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