3000rpm mis-fire !!

johnny.1953 · Nov 19, 2010

Hi,help 1999 Discovery 2 ES Manual. 95,000mls
When car is revved to about 3,000revs it appears to run rough/mis-fire getting really fed up with it. So far been at main dealer,three Indy specialists. New maf,injection loom,main engine loom . Fuel pump checked out ok,all filters changed full service by Indy. Main dealer no use even after two times on analyser.
Anybody any ideas please or is it time to burn it!!!

Dingly · Nov 19, 2010

Is your car fitted with any of the after market power chips such as PSI?

Does the problem occur at light throttle openings and constant speed or under heavier acceleration?

Dingly · Nov 20, 2010

Still thinking on this and realised that your culprit may well be the in-tank fuel pump.

johnny.1953 · Nov 20, 2010

Hi Dingly
Thank you for your reply,no it is a standard ES,mis-fire comes in at steady 3000rpm,engine is fine up until then and also when past 3000!!
When tested fuel pump pressure was good.
Thanks again

Dingly · Nov 20, 2010

The internal pump can display signs of malfunction at a specific rpm and then show no signs of trouble elsewhere in the rev range. This has been documented in a recent LRO.
Good luck in getting to the bottom of this.

thebiglad · Nov 20, 2010

johnny.1953 said:
Hi Dingly
Thank you for your reply,no it is a standard ES,mis-fire comes in at steady 3000rpm,engine is fine up until then and also when past 3000!!
When tested fuel pump pressure was good.
Thanks again

Hi Johnny, ideally you want to get this onto a diagnostic terminal to find out what's wrong, but a cheap fix to similar sounding problems is the wastegate modulator - costs about £20 and takes about 15-20mins to do.

www.discovery2.co.uk / Waste Gate Modulator - Over boosting

Cheers
Dave

3000rpm mis-fire !!

johnny.1953

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thebiglad

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