corsa lack of power

Yeah & if you do find out what's going on then most of us would appreciate the answer.

I'd go with hot air under the bonnet causing a flat spot. Maybe the whole air inlet system is getting above 60 degrees in traffic. Maybe the air is being sucked in from a cold area (up front) but the whole air system is so hot, the air going through it catches some of this heat???

Maybe you have a boy racers citroen axgt which has a k and n air filter mounted behind the hot engine in the worst possible hot place, gaining 8bhp only when you're doing 120mph (with associated air flow). At all other times its -15bhp.

its possible. I was stuck in traffic on that day for a few miles then at lights for a bit before going straight onto the motorway.

Is there any solution to the problem?

Hm, well it's a very slight incline upwards, but then again, it doesn't seem to do it on other hills... plus, the clutch seems fairly normal, its not high or anything.

There's a big nerdy article on this on my website, but without bonnet ventilation, not really.

Are you using the standard induction system?

Insulate the whole inlet manifold/air flow meter/air filter from radiated heat .... maybe wrap them in shiny foam/foil. Anything to stop the "sides" of the air passage from getting hot. Bit overkill to be honest ... modern cars are designed to work in all conditions and all situations, so maybe the flatness is better than a no runner??

Yes!! ;)

if it is an airflow problem, could it not just be the maf needs a clean / replacement? Or am I totally lost...?

If its of the hot wire type no. (As fitted to my 1989 bmw). It could be a flapper arrangement, which arn't as reliable as the hot wire type, although on my mates bmw which is older than mine (1987) his is perfect at 415000 miles. I'd imagine the corsa is tuned to meet emissions and fuel economy standards ... one trick known to be used by many manufacturers is to tune the mixture to be as weak as possible at the revs which match 56mph ... to give the best 56mph fuel consumption figure. I've read of this several times on vauxhalls. Maybe your flatspot is linked to this deliberate weak tuning. See what revs you are doing at 56mph in top. See if it occurs at these same revs in the other gears??

Failing that, buy a hatchback which is 250kgs lighter, than your corsa, giving better acceleration/fuel economy for a start. Then re-engineer the engine to produce 128bhp.

I did ... the most fun car i've ever owned!! Flatspots are VERY abundant in my car running performance cams,etc.

They used to, but it's largely been stopped owing to the new ways of calculating fuel consumption.

[snip]

thing is its not simply a flat spot. It dosn't always do it, if it were a flat spot surely it would always be there? If it was the clutch surely it would do it more in higher gears, the revs would go up as the clutch slips, but speed would be the same. It only seems to do it after I've been coasting along fairly slowly in traffic to some lights, then accelerating away. Had the cara bout 4 months now, and its only started oit recently. It did it agian today, and again yesterday... Thing is, I can't pin point it exactly what is the one different variable that's there when it does happen, compared to when it doesnt happen. So far, its the coasting and waiting that seems to be the key. So eprhpas as someone said, it is just warm air building up. Induction doesnt look very big, looked to see if it was blocked before, perhaps by a hamster or something. Maybe I should add some 'speed holes' to the bonnet, a la Homer?

Or I could live with it, unless it gets worse... But not a problem at the mo really. Just annoying!

Think I might try some things. When I get back home, sit in the car, wait ten mins, and then rev it...

Cheers

well, i might give that a go anyway :)

What's the weather like when it does it?

warm. Though didnt do it today, and was warm too. But traffic wasnt as bad, wasnt stationary for very long...

Thing is, it doesn't have to be especially hot. When on the "overrun," the induction system tends to get backed up with warm air, and when idling it typically doesn't clear - but instead it does so when you accelerate.

The above is only based on our Ka's induction system temperatures, but I'd imagine that the Corsa isn't a million miles away.

But I cannot see it causing a big hiccup to be fair... :(

The clutch may well slip in the high gears but because you have a substantial momentum you will not notice the problem

Think how the clutch system works - You are slowly cruising in a low gear then you accelerate - the gear/clutch are engaged - the strain the clutch/gear is going through to increase motion at this point is massive and you will notice the slightest slip - if it slips it will feel like no power for a split second. Pull away going up a hill the stress is even more and the feeling of lack of power will present itself greater than usual. Of course pulling away down hill the stress is not so high therefore evidence of lack of power will not be present.

Had

May be the car orginally had a clutch problem and some how its had a quick fix?

Thing is, I can't pin point it exactly

That's the first sign of a clutch going. You will not notice a clutch slipping while travelling 55-70mph and changing gear from 4th to 5th

Hi "SDD"

415000, is this still on the original plugs and oil??

The message from "Steve Sweet" contains these words:

Please sir! I had a Fiat 127 followed by an Austin 1100 estate then a

1500 Allegro. Then a string of company cars including loads of Corsas (which really were vile) then Maestros.

I've just moved up to Montego.

I said my mates bmw. Not my taxi driving mates nissan bluebird!!!!

LOL!!!!