Hi,

I have a 2006 Octavia VRS which has developed a problem after travelling down a bumpy track.

When cold, there is a constant rhythmic misfire which clears itself after about 15 minutes of warming up. Once warmed up, the car operates perfectly. It seems to be worse on damp mornings

The engine management light comes on, but sometimes goes off again and sometimes flashes.

I took it to a dealer who checked for errors and found a misfire on cylinder 2, they checked all the spark plugs and tightened the igniter, but the problem is still there. They suspect a faulty igniter but are not sure.

Recently, I have noticed a slight burning smell from the rear of the engine so think it might be insulation break don somewhere or a coil.

I originally thought that the bumpy track has dislodged something, removed a vacuum hose or that the Lambda sensor had taken a knock.

Any suggestions gratefully received.

Thanks

Pete

Given the info in your post I would try a new #2 coil first. I assume the plugs were found to be good?

Coilpacks mate. They go all the time on TFSIs

Thanks, will whip it out now and have a look and a snif.

Will also disconnect it while running lumpy to make sure its the right one.

Pete

Quick tip: Use a looped cable tie to get beneath the head of the coilpack to pull it out. Just makes it a bit easier

Hi,

Fitted the coil pack and thought it was all sorted, but when I started the car from cold this morning, the problem was back.

Moved the new pack from cylinder 2 to 3 as the Dealer was initially a bit confused as to which cyclinder had the misfire. Still the same problem.

Sorts itself out after about 15 minutes and the car is fine again

When the car is first started, its almost like a rhythmic pulsing of the engine, not sure if this is the misfire, or is another problem that is causing the pulsing and leading to an occasional misfire that is noted by the ECU. Maybe something was shaken loose somewhere.

There is also an unburnt petrol smell from the exhaust.

The dealer originally said that they suspected a faulty igniter, but I have not heard that term used before...

Thanks

Pete

Edited 18 August, 201015 yr by OracsRevenge

Does it use a lot of oil?

It has always used a fair bit, need to top up monthly to keep it above the line.

The issue I have appeared after a trip down a bumpy track and seems worse in the damp.

Thanks

Pete

Hmm just sounds similar to how mine was when i bought mine thats all. Mine used to misfire first thing in the morning and then was fine after the first 2-3 miles. It's quite common in the Tfsi range and is due to carbon build up mainly around the inlet manifold ( due to direct injection). When I bought mine it was a high motorway mileage car and hence not given a hard time and prob bunged up with carbon, prob around the piston. It took me a few months with vpower and a bit of thrashing to get it running right.

Mine also uses a lot of oil

If yours occured after a bumpy road then maybe it's not that....

Spark plugs?

I'd suggest checking all the connectors you can see by pulling them off and then pushing them back on again.

Also if you're using a lot of oil, then I guess you may have coke in places that could potentially have been dislodged if it was very rough.

I have to replace a coil pack on mine, same car, does anyone know how to remove the airbox that goes over then engine to allow access to the coil packs?

Take off the maf sensor clip and unclip the pipe which attaches to the cover at the top left. Use pump pliers of similar and unclip air intake cowl, and pull the cover straight upward and off. You need to give it a good tug as it's attached by four lugs. On refitting it's a good idea to put some silicone grease on the lugs to make removal easier next time.