Hesitation 3200rpm on constant light throttle

[dse444]

Why should the engine hesitate at 3200 rpm. When accelerating gently, on constant throttle, the engine always hesitates slightly when reaching 3200rpm. With large throttle openings you just don't notice.

Does the engine mapping or something switch over at these fixed revs?

[beano500]

A number of possibles.

In my experience, hesitations at various points of the rev range have been linked to the HT leads being due for replacement.


But check all the HT connections - when was it last serviced - how's your stepper motor and is there an "R" in the month?

[GreenV8S]

I don't know if it is exactly 3200, but I understand that the ECU drops out of closed loop mode at a little over 3000 rpm. This is why lamdba sensor faults only show up below that point. Doesn't really explain why you get a hesitation just at this point though.

[dse444]

Thanks for the ECU info. The dealers have swapped the lambda sensors this year, and fettled a few others, which improved it for a while. Back to the dealer....

[spend]

Could this be when the purge valve is opened?

Mine used to stutter a bit, improved when discovered pipe from valve - canister had come off. Note not all have separate units, my LR has later integral valve and carbon canister.

Dave