Engine stutters and car lurches under accelerator lift off at low speed

I have fixed this issue. But has anyone experienced this.

In 2nd gear in traffic doing 10-15 mph lift off accelerator and the engine braking turns into a jurking and lurching forward as if the car is kangerooing like before you learnt how to use the clutch and bring it up to quickly with revs to low you don't stall but the start to jumping forward in lurches one after the other.

there was no issue when driving the car normally. Only when coming off the throttle.

This was happening even when I was being really gentle with the clutch.
It was starting to annoy me.

So I had a think and went through the usual suspects.

Coil pack
Plugs
Leads
MAF
IFS.

Non of which helped the issue.

So I did a boost leak test for good measure, because I can.

Well this showed a leak on my small boost pipe that went from the red tip pipe to the T piece that splits the boost pressure to both waste gates.

When I say leak the pipe was connected but was split so any kind of boost pressure would leak out and any kind of vacuum pressure would suck in unmetered air to the engine.
This vacuum leak, unmetered air is the key issue.

When the engine is off throttle the leak makes it run very lean and it is this that causes the jurking and lurching.

I replaced the vacuum/boost pipe and the issue has gone.

So if anyone else has this issue.
I hope this description helps you sort out you issue.





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oooh, interesting. I've noticed that mine has just done something similar when I came into the carpark at work today. I was also getting a similar feeling (more through the pedals than actually with the car lurching) when I was off the accelerator with the engine was idling at around 1500rpm, about 40mph.

I'll begin an investigation this evening and report back when I can crack it. Thanks for the pointers.

Stuart

Nice info Dave :)

Definitely do a boost leak test if you can.

The vac/boost pipe I had were rubber covered in braid, the pipe split but the braid cover it up.
So I would not recommend this sort of pipe for the engine bay the rubber could not cope with the heat.



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