159 TBI Flat Spot

[anonymous-user]

Hello all.

Occasionally when accelerating (not hard) my 2009 TBi hits a flat spot for a second and stops accelerating. It carries then holds the speed it stopped at until you release the throttle and reapply it.

I thought it was perhaps sludge being dragged up from the tank (is that still a thing?) but even after filling up it still does it once in a while.

Are they particularly sensitive to the type of petrol used?

Has anybody experience of this problem? Thanks in advance.

[Lesgrandepotato]

Mine doesn’t do it. Well not with any frequency maybe 3 or 4 times in 40000miles.
Think it’s an overboost thing. Wonder if you have a leaking boost hose?

[anonymous-user]

That's something I'd never have thought to check. I'll get it booked in and mention it. Thank you.

[allegerita]

Did the car ever have any sort of chiptuning (I believe you call it ‘mapping” overthere)?

I occasionally experience a similar yet only vaguely noticeable behavior. The weird thing is that it happens with slow acceleration at low revs and low turbo pressure. Weird in the sense that if it were a boost issue you would suspect it rather to happen at high pressure.
My car was chip tuned so maybe there is a hiccup somewhere?

Edited by allegerita on Friday 24th June 08:35

[anonymous-user]

Not that I'm aware of but again, I will look into it. You're right when you mention it happens at low speed or when the engine isn't being pushed hard.

I experienced fuel starvation in an old Mk1 Gold I had and that caused the car to splutter and drop revs, whereas this maintains the momentum but refuses to accelerate or increase the revs.