Hi everyone. 

Help needed again with my beloved Yeti 1.2 tsi.

I changed coil pack, leads & plugs only a week ago due to a bad misfire on cylinder n°3.

Everything seemed perfect for a week until I noticed a kind of "coughing/sputtering" when I accelerated harder on inclines. If I accelerate gently and let the car pick up speed without pushing too hard, it's seems absolutely fine. Otherwise the car runs perfect. No warning lights, either.!

Any ideas greatly appreciated 🙏 

Injector related ? My previous Audi started doing that when revved. Replaced all.

Or turbo and related pipework?

Edited 13 May, 20242 yr by Prezafab

^^^ Well if needed then fine.

 

As it is did the spark plugs need replacing @Kirky ? They are a 4 year / 40,000 mile item/

Were the Coils needed replacing though?

 

Has cylinder 3 got the armoured lead.  The one that can cause misfires.  Was there an armoured one fitted then replaced? 

 

What age is your Yeti & how many miles has it done? 

 

 

Edited 13 May, 20242 yr by Ootohere

@Ootohere she's a 2012 plate, with just 60,000 miles on the clock. According to service record, the spark plugs were last changed 5 years ago, just before I bought the car.

So, I thought it would be good practice to change plugs, leads + module.

I fitted :

Bosch FR6HI332 Plugs

NGK 44316 leads

Intermotor standard 12919 module.

 

The old HT lead to cylinder 3 looked shot, when removed, so needed replacing. N°3 spark plug also looked very sooted at the bottom. 

Old vs new....

 

 

 

 

?

Is there a nice clean air filter fitted? 

Will check the air filter tomorrow. Its been about 4 years since last changed, although I only do about 6k miles per year, so wouldn't expect it to be too bad. Thinking of also changing the fuel filter & a regular dose of Redex !

Any idea where the MAF sensor is located ? Maybe that could cause such issues ??

 

Give the REDEX a miss. 

Better just use E5, even Sainsbury Super Unleaded 97 min. 

Mileage hardly matters with Air Filters it is location location location that can have then choked.  Countryside.  Wildlife.

 

 

Edited 13 May, 20242 yr by Ootohere

Hi

 

No harm in changing the fuel filter to eliminate it as a possibility, but I doubt this will have any effect, I suspect they are mainly fitted for countries where fuel might occasionally have solid contaminants.  In the UK a fuel filter should last as long as the car.

 

As cylinder pressures rise with opened throttle and turbo boost, the plug firing voltage increases.  If the ignition system doesn't have enough reserve for some reason this can bring on a misfire under those more demanding conditions.  You seem to have changed all the components but it might be worthwhile having another look at the multiway connector to the ignition coil pack, i.e. the low voltage and control side, just in case there is any corrosion or a chafed loom wire.

@Austin 7 thanks for the info. I will check it 👍

Bump for @Bertie90

what I would do next is either swap injectors around to see if the issue moves to another cylinder. If not then do a compression test. You've done everything apart from these 2.