Hopefully i can help..
The missfire you mention would likely be factor in the emissions issue the ecu is picking up on.. ideally i would suggest finding out what actual fault codes you have logged in your ecu..that normally the first step any garage takes with problems like this..id say from what you describe in regards ***** ***** missfire might suggest ignition fault/ ignition coil/fail sparkplug. or injector fault..because its emissions related then it means your not getting complete combustion so exhaust sensor are seeing this hence the emissions warning and could damage the cat converter and destroy it over a period of time..i would suggest having it seen to sooner rather then later..so as above that about the best way forward on this one..i do hope this helps
Have you any idea of the likely cost of having this issue looked into by a non-Vauxhall garage? Im a single mum to 5 kids and would appreciate your honest opinion on this if poss as i hate the thought of being ripped off!
Fully understand.and wouldn't really advise going to the dealer with fault like this..best approach is to have the car diagnostically tested as I highlighted above first to see what fault you have logged.normally a lot of garages vary cost with that some £25-£45 per test.this should help any competant mechanic who knows how to use the diagnostic machine and solve the issue without just throwing parts at it - at your expense.. the best place to check first id say unless any family member knows of a good agarge to take your car too or one you take the car too ..or maybe try this site www.goodgaragescheme.co.uk and find someone local on there or near by..
but as it stands it would be hard to say the total cost on the job itself without known what sort fault you have//only once the testing has been will you get an idea o costs..but if you need a second opinon after that done then your more than welcome to come back here and ask myself should you require anything further help..i do hope this helps further