Vectra misfire

it would most likely be a sensor failing when it is hot, it will probably recur. Next time it does then get the codes read. Both camshaft and crankshaft sensors are a regular fault on those (as are bad connections to either)

Could be a sticky egr valve not closing properly due to gunge.

Thus spake rp ( snipped-for-privacy@infohit.me.uk) unto the assembled multitudes:

My GF had this happen with her Corsa. The dealer disconnected the EGR (she didn't want to pay $$$ for a new one) and it runs fine now.

So just pull wiring socket from the EGR? Will the engine management light stay on all the time? I dont suppose it really matters though if it runs OK. might try as temporary measure, as its weekend now. Thank you all for replies so far.

It depends on how it's operated. On mine there is a stepper motor and if you pull the plug you get the engine management light on. As I understand it there are some that use a vacuum servo and if you removed the vacuum hose and plug it you don't get the engine light. I took my valve off and put a sheet of coke can between it and the mount to seal it off and it's been fine ever since.

Thus spake 4square ( snipped-for-privacy@whsmithnet.co.uk) unto the assembled multitudes:

No warning light comes on in my GF's car. I don't know exactly what the dealer actually did, but basically they did something that stopped the sticky EGR valve from upsetting the engine management. Whether or not that was a simple plug disconnection I don't know (I am after all relying on my GF's slightly sketchy description of what they told her!). I'm not sure however if this solution would result in problems at the next MOT.

some vauxhalls can have the ecu reprogrammed to remove the egr from the program, unfortunately this only applies to certain models/ecu types. the egr sometimes just gets a bit of coke stuck in it, which is enough to ruin the idle, sometimes it comes out on its own. having the egr working or not does not seem to effect the mot emissions afaik.

Taking it in to local independent garage for diagnosis this afternoon. From my description, they suspect the coil-pack, something failing when hot. I shall let you know the result.

Thus spake Mrcheerful ( snipped-for-privacy@hotmail.co.uk) unto the assembled multitudes:

Certainly before my GF's car was 'fixed', the engine sounded like a diesel when it was idling, and acceleration was uneven and poor.

s:

Took to garage, with EML on. The analyser read 'coil pack fault', and no other faults. Fitter replaced spark plugs with new ones, and fault gone, EML out and running well again. Car was OK on way home, and tested it again this morning. OK for about 20 miles, then when hot, EML on again, and running rough. So, I reckon a new coil-pack needed. About =A3100 I think.

I find it a bit odd, that the fault went with new plugs at garage, when the engine was hot at the time. There does seem some inconsistency here. Does make me wonder if its a bad connection but that would surely be same when cold or hot engine?

there is a known fault with the connector to the coolant sensor, vauxhall make a kit of bits with gold plated connectors to cure it. there was also a problem with a bad earth on the ecm. but my money is still on a crank sensor. and crank sensor did not show up on the fault codes on a diesel vectra I did the other day, yet the sensor had no connection through it at all ! and replacing it cured the problems: rough idle, low performance and no rev counter.

This is getting complicated! Where is the coolant sensor please? And what does ecm stand for? Gold-plated connectors sounds a bit extreme, these are only cars!! My rev-counter is working.

Another thought, if it is a crank or camshaft sensor, do these faults only occur with a hot engine, or when they are cold as well, that is, would it be evident from start-up? The present fault is only with a hot engine.

the crank sensor usually first starts to fail when hot, turning off for about ten minutes will usually restore the situation for a short while.

the ecm is what vauxhall call the main computer.

the ect is iirc on the top left front of the engine as you look from the front.

the wiring fix basically makes the wiring a bit longer and improves the connection, so if the connections are good and not strained then it is probably ok

Finally......fitted new coil-pack, =A3105 from Euro-carparts, on Monday evening, running OK since. Thank-you all for replies and advice, has been most informative.

I am glad it works!!