Corsa AAAAAAAAAAAAAHHHHHHHHHHH

Tried the MAP or MAF sensor?.

could try putting old plugs back in if you still have them, or get a set of standard ones they only cost about £8. worth a try. also i know its a long shot but the New idle air valve and New egr valve could be faulty? the trouble is with "modern cars" there is so many things that can cause bad running, a friend has a 2001 astra similar probs and had the main ecu replaced under warrenty still the same eng lamp on. then the dealer replaced the cat no more problems,car had done 40k

It's a long shot and this is only anecdotal: a few years back I "upgraded" the wife's 80k miles VW Golf GTi to Bosch Super 4 plugs ( I think these are what you have). Immediately afterwards starting took noticably more cranks to get going, cold running was piss poor, and even when warm there seemed to be something sluggish about the car. Cleaning the standard Bosch 3 prongers and putting them back in cured it all!

Ditto a TR7 V8 a few years ago: Bosch Super 4 plugs gave the same symptoms.

Can't quote any physics to you, or rationale behind this - just know it happened to me.

-- Ken Davidson

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Some manufacturers specify multi-electrode plugs as they wear more slowly, enabling longer service intervals. There is no point fitting them in a vehicle which doesn't have them as standard. Most modern engines burn very close to 100% of their fuel with standard plugs, so changing to a multi-electrode type will not improve this. According to NGK (who know a thing or two about spark plugs) even replacing badly worn plugs will only gain 1-2% power. I would always fit an OEM plug, or it's direct replacement from a reputable make.

Thanks to all for their answers thus far. Where the cat had been changed i found that they had cut off the new plug and just crimped and taped wires to the new cat wires .

These were all loose or falling out, however after sorting this out the problem still persists Cleaned all plugs. they looked a nice light brown Still no joy will try exhaust tommorow

The one constant thing in all this is that when in tickover Boot down hard produces a situation where the revs go up in absolute stages.

1k to 2 k then engine hunts for a bit 2k to 3k then hunts again 3k to 4 and so on. If accelerator pressed slowly engine revs go up in a smooth manner. The Canned History of this problem

It was checked on a diagnostic more than once by main dealers some 6 months ago

At various different times they have, via the diagnostic error codes, put the problem down to cat,idle air valve and egr valve.

The work was all carried out by dealers in kent.

The problem still persist.

Currently. Tried ringing my local (Cornwall) vauxhall dealer today

asked for a price to have it put on a diagnostic was informed this would be about £30.00 inc vat ( reasonable ) but was then told the following -:

A Diagnostic would only show last error and whatever it showed it may not be that part that is faulty, because a diagnostic will only show in what area to search for the problem.

I then said that according to the manual, the error values reset at every tenth start so therefore there should be one in 10 chance of showing the last ten error codes.

No says he,it would only show the last error.

He than said What people normally do is bring it to us and we will investigate and put it right.

As my son has spent a bloody fortune on this car already and got nowhere with other so called 'Main dealers ' handling the job.

I am very unwilling to let anyone take yet more money.

Is there any other way i can a- read any errors myself b - get someone other than a main dealer to give me a 'proper' reading.

(Ps My own old car has a Distributer and points with No Electronic EMS as such HooBloodyRahhhh )

Have you tried going to the Vauxhall dealer's parts department and getting a standard set of spark plugs, and putting them in? As others have said, super-4s will probably have next to no effect compared to the standard plugs, and there could be the chance that they're not set to the right gap. The genuine GM ones more likely will be.

Have the Vauxhall dealer tried replacing the plugs with standard ones?

Peter

Right. Put the genuine plugs back in first, dont bollox around with snake oil multi pronged plugs etc etc, if the manurfacturer thought it needed them, it would have fitted em. You can get all sorts of problems of stray HT and back EMF being created which is upsetting the ecu, so rule this out first.

You have correctly checked items first on the list that would likely give this problem that I would have- i.e. the Cat and then the EGR valve, but did you also check the rest of the exhaust for bits of old cat or other obstruction eg baffles collapsed. Drop the pipe off aft of the cat and go for a short test drive (embarressing if you dont live in the country!)

I would then check very carefully the wiring, with particular attention to the screening connections (both ends) of the MAF, CAS, CPS, and the routing thereof near the coil pack- basically where ht could be induced into one of these cables and upset the ECU.

If all of this checks out then disconnect the MAF and go for a drive. The MIL will be lit constantly, but if the car drives any better then the MAF is at fault. Its usually the diesel MAF's that go faulty on Vx cars but petrol ones occasionally go to.

Tim..

Cheers all

I will sign on again tommorrow night and let you know of the progress