This is addressed to the professional mechanics or representatives of Skoda dealers out there.

As you may be aware, I've been struggling with a misfire on my Octavia for a year now. I've carried out many preventative measures, but it's back, and I want it fixed. However I don't trust my local dealer to the extent that I want to just hand over the car and say vaguely - it's misfiring, because I know the problem and the various remedies I've attempted, and I know all the things it ISN'T.

What I'd like is to be able to take the car somewhere where I know there is an expert who understands the problem, and get it fixed once and for all. The car's also due an 80k service quite soon (it's on 76.5k currently) so it could be wrapped up with that, since that requires a cambelt change anyway. (I know at least one expert reckons it's valves, which means having the head off) It's an AGU engine, so the coilpacks are of a different design to those you vRS owners are familiar with, although I did have one fail in the early days of ownership.

Things that HAVEN'T fixed the problem:

1. Coilpack

2. Cleaning the injectors

3. Cleaning the MAF

4. New plugs (seemed to have fixed it, but NO)

5. Engine treatment - both FORTE and REDEX (although the REDEX did seem to keep it at bay for a good while)

So can one of you experts fit it into your service inbook? I'm not asking for anything free, or discounted, just the knowledge that someone who knows what they're doing is carrying out the work, and won't spend days or weeks chasing wild geese, with me picking up the bill for their uncertainty. Alternatively if someone good can be recommended I'll approach them as well.

I can supply more detail if anyone is interested.

Why not visit the Honest John website - you should find many tales of misfiring in many makes of car. The Honest John cure? Shell Optimax petrol ! Try one of more tank fulls

It worked for me with another make/manufacturer and my own Octavia 1.8T is a different animal after one tank ful

Optimax solved the "pinking "on my bosses Ford Cougar. He alternates, one full tank of optimax to 2 tanks of "normal"

Did I mention the car's almost exclusively fed on Super Unleaded / Optimax?

It's not "pinking" - it's one particular cylinder.

Thanks for the replies though guys

Nick if you car has a misfire and also has a Cat I should imagine the cat is now fooked.

Well it went through its MOT 2 months ago without any comment.

Couple of questions firstly...

Is it missfiring all the time?

Have you had the compressions checked?

Ross,

You have PM. Thanks for taking the time

you know my feelings nick

Its an interesting one, and im thinking along the same lines as you mate.

Compression check should say one wayor the other though, as long as its missfiring at the time.

So will just a cheap Halfords compression tester do the job? If so I'll get one...

Yeah should do, not saying you wil find anything but if you stuck go back to basics, do you have spark, fuel, air and compression on each cylinder?

Pull out the J17 fuel pump relay when your doing the test, that will cut the spark and fuel, the relay is located in the small black plastic relay carrier in the engine bay on the right hand side as you look at it, at the back behind the air filter.

Ideally you should be looking for around 10 bar per cylinder, but whats more important is that they are all around the same.

Well when it was happening at the start I swapped plugs, coilpacks and injectors from one cylinder to another. I thought I'd identified a dodgy injector, sent them for cleaning, and sure enough the dodgy one was the one with the worst spray pattern, but as soon as they were back in, the problem reappeared. Jabbasport who cleaned them said there were no injector missed pulses during their tests, so it wasn't that. I will have to start the process again ... :(

Firstly i am no mechanic ...but have experienced this with a rover ,you said the redex treatment worked for a good while did you put it in the petrol or through the plug holes ? i did the latter ...warm up the engine, stop, remove the plugs pour a cap full in each hole wait half an hour cover holes crank engine over aa few times then refit plugs ..it worked for me might be of no use to u but as i said it worked for me..

Good luck

Tried both ways - originally down plug holes, then a systematic regime of dosing the petrol over several months. The plug hole treatment did nothing (understandable if the problem is in the valves) but the petrol treatment seemed to. I still have a big bottle in the boot, but I got lazy of late. Best start again ...

Well, heartfelt thanks to Jon (TaviaRS) for coming out of his way to look at my car with VAG-COM and check for fault codes. The bad news (not that unexpected) is that there weren't any. So back to square one - manual diagnostic methods.

More beer I owe you, Jon. :cheers:

No worries Nick, happy to help

or at least try to