High speed 'kangarooing'

[zebedee]

Whilst out on the excellent Midland's club blast yesterday I noticed that sometimes after lifting off from high revs in 3rd gear and 2nd gear the car was lurching, such that I had to push the clutch in to smooth it out. Its a bit like the kangarooing that you get when you learn to drive and haven't got enough revs on - but its happening at 50-60 miles per hour! Its the 111S series 1 (VVC) if that makes any difference - what can it be? Someone said something about re-setting the ECU - but how do you do that?!

[fergusd]

Some questions before a guess . . .

does your cooling fan work as you'd expect (not the temp display but the actual fan) ?

Have you checked the engine steady bar bush ?

Fd

[zebedee]

yep - heard fan running away fine on sunday, temp reading was normal. not sure about the engine bar bit - whats that - and whats your guess?

[DanH]

My guess would be some problem with supply of fuel, but you need to take it to a garage to investigate. The problem might be logged in the ECU.

[zebedee]

i am going to upgrade to optimax so i'll wait until i've put 3 or 4 tanks of that through and cleared out all the nasty 95 octane rubbish I've been choking her own (shame on me)

[fergusd]

Well . . .

If it's nothing mechanical, like an engine mount or suchlike, you need to get this checked by someone who can check them . . .

I had perhaps similar intermittent symptoms when I had a bad connection to my ECU temp sender, sometimes I'd get a very jerky response when lifting the throttle, especially ah higher revs.

I would expect running 4 tanks of optimax through it to make absolutley no difference whatsoever, presuming you have a standard engine, apart from you your bank balance . . . ;-)

Fd

[zebedee]

thats not what a lot of people on the sunday midalnds run said - they couldn't believe i was running it on 95 octane - apparently you don't notice the difference until you fill up with 95 again (out of necessity) - I reckon its worth a try. It doesn't do the kangaroo thing all the time, so I'll keep my eye on it...

surley it has to make a difference to performance running 98 as opposed to 95 octane fuel? May need to post this debate under another thread...

[zebedee]

second thoughts - have just searched archive and there is no point using it as K series doesn't have knock sensor so won't adapt - ah well - few more £ saved!

[gargamel]

swith the ignition on

depress the accelarator four or five times all the way down. switch off and then restart after about a minute

I think this resets the fuelling -

[DanH]

Yep optimax shouldn't make any difference, although potentially it might give the engine a nice clean