4.2 slight hesitation around 2000 rpm

[Erich Stahler]

Notice recently mainly driving in 3rd in slow traffic around 2000rpm, sounds like its not quite running smoothly then a bit more throttle and engine note changes to what it should sound like and power picks up. I was noticing this today and while driving on a dual carriage way in an 35 speed limit, was starting to become convinced its the plug leads breaking down, however judicial application of my right and it accelerated away into the distance just as ballistically as a Cerb should do, so I am kind of dismissing the leads theory as engine runs fine at higher rpm with no loss of power or hesitation.

The other possibility is that I have been a bit slack about always using 98 or higher octane petrol, quite often use 97, so maybe the engine map has adapted slightly to a lower octane?

[Mr M]

Hello Erich. That seems quite low revs for 3rd gear (edited and realised you said slow traffic - sorry). In fact I was going to ask here on the merits of using 98+ over 95. My tank has a silver sticker next to it that say's 98 ron only so though it pains my wallet to do so I tend to stick to the advice. My 4.2 had a software upgrade done at Austec in 2005 by previous owner, which is where I think the sticker came from. Perhaps yours has too ? I would be interested in a professionals view of using super unleaded over regular. The sales guy I bought my Tiv from thought it was all a bit of a con but he did want to sell the car as quickly as possible.

Edited by Mr M on Sunday 20th April 13:11

[V8 villan]

hi Mr M

i'm no professional but can offer anecdotal experience that confirms these cars perform better on super than regular

there's no doubt that my car does not like anyting other than super and loves shell v power. there is a definate loss of crisp acceleration if i have to use regular and the pinking is terrible

i'm afraid the £1.15 per ltr is something we have to bear if we want to get the best out of the cerb... imo

[Ballsy]

I had the same problem but it when when the revs were around 3k, turned out that one of ma lambda sensors was knackered!!

[Mr M]

V8 villan said:

hi Mr M

i'm no professional but can offer anecdotal experience that confirms these cars perform better on super than regular

there's no doubt that my car does not like anyting other than super and loves shell v power. there is a definate loss of crisp acceleration if i have to use regular and the pinking is terrible

i'm afraid the £1.15 per ltr is something we have to bear if we want to get the best out of the cerb... imo

Ok V8V - Maybe Erich should stick to 98 to start with and see if the problem still continues. A process of elimination.

[Erich Stahler]

Thanks guys, I think i will use decent fuel, 98+ frokm now on, and keep an eye on the situation.