Hi,

I have a Octavia Vrs 56 plate with approx. 80K miles. A few weeks ago something changed and now I have what I would describe as a slight misfire/flat spot?

Here's the clues;-

- Fully "long life" serviced at main dealer - last on 2 weeks ago.

- No problem starting cold/hot - fires first turn.

- Engine idles fine - approx 1200 rpm when cold, then drops to approx. 800 rpm after a minute or two.

- Engine revs smoothly when not driving.

- Seems to have lost the bottom end torque - I used to drive around town in 6th no problem, smooth as you like, now I'm down to 4th!

- At lowish revs in say 4th/5th when I floor it, there is a delay, then the turbo seems to kick in and accelerates fine. It used to pick up immediately.

- At motorway speeds in 6th, again, there seems to be "turbo lag"?

- When trailing the throttle it seems jerky - I'm constantly dipping the clutch at junctions.

- When under load at low speed, I hear "pinking" occassionally.

- No warning lights on dash.

- Checked at dealer - no faults found / no codes being thrown.

- I may be wrong on this one, but to me it sounds like the exhaust is blowing slightly, but the mechanic said not...(not sure on that one)?

From other forums I suspected the coils. Although I haven't replaced them all, I did buy one, and try moving from cylinder to clylinder...no real difference.

I changed the crankcase breather valve (old one was a little gummed up) - no difference.

I've run through a tankful of Slick50 injector cleaner with Shell Optimax - no real difference.

Now I getting stuck and reluctant to change many more things as I could just be wasting money.

Anyone any thoughts or suggestions??

Cheers.

I've had the same thing, after running the car on lovely German and Belgian V power in May, a slight intermittent misfire under load (mainly high revs / speed). I tried Redex which was a failure, but have just tried STP power pack (from Hellfrauds) and thus far, it appears much cleaner running and better through the range. Just a suggestion.

Nick

Poor fuel quality? Try BP Ultimate. Stopped the pinking in mine.

Poor fuel quality? Try BP Ultimate. Stopped the pinking in mine.

Yes, thought that, Shell at Fontwell - my usual garage has been shut for a refit, so ive been to rustington, seems as if troubles are behind me again as Fontwell is again open....

this may be miles off but its just a suggestion, mine started doing roughly the same thing, round town it would be jerky, bogged down and rather unpleasant to drive and on motorways it would feel like its a little clogged up and takes a second or two to get a move on.

As for the pinking sound i dont know what to suggest as i have not experienced that with mine but your symptoms seem similar to mine.

I took mine back to the dealer and they suggested the gearbox oil, as this is your engines last port of call for power and i there is nothing wrong with the engine then its worth doing. Im going to get mine changed on wednesday and see if that smooths things out.

As or the fuel, that could be good explanation but surly you would see a difference in mpg? And if it was poor fuel that was blocking up the injectors i think it would seem apparent at any rev range i.e idle, under load or cruise

hope this helps

I suspect that poor fuel can cause momentary hesitations in the burn, rather than clogging up. Mine certainly never looked back when moved from supermarket to a premium higher octane good brand name fuel.

I suspect that poor fuel can cause momentary hesitations in the burn, rather than clogging up. Mine certainly never looked back when moved from supermarket to a premium higher octane good brand name fuel.

+1

Years ago I put a tank of dodgy fuel in an old Rover 216 GTi, it ran like a sack of sh*te, I panicked until I went back to my normal Shell (standard) fuel. Back to normal, ran lovely...

Fast forward a few years, I have an E36 328i petrol and an Octavia mk1 1.9tdi - both perform much better, smoother and more economical with Shell fuel than anything else (even better when I treat them to a tank of V-Power) 4-5mpg sometimes!!!

Stick with better quality fuel, use injector cleaner every few thousand miles... It's worth the extra 1-2p per litre and your car will love you for it!!!

Incidentally, I don't use BP 'cos they're always the most expensive!