First of all hi to all in the forum this is my first post (long time reader)

 

So this is my problem, if anyone can shine some light on it it would be much aprecciated.

 

I have a skoda octavia 4x4 TDI 2002 model.

 

Symptoms are INTERMITENT but getting more and more frequent.

 

Slight rough idle (only slight)

As soon as i put my foot down the car goes, but it jurks rapidly and constantly weather im accelerating or maintaining rpm. (dont think its limp mode as the power is there), its basically like being shacked rapidly in the seat while driving.

 

Like i say the problem isnt always there, which leads me to belive its not a mecanical issue??

 

most of the time if i kill the ignition while on the move and switch it back on it cures the problem. Allot of the time i have to pull over stop fully wait a few seconds and try again. sometimes this works other times it doesnt.

 

Things ive tried already:

 

new diesel filter

new CTS coolant temp sensor

Mr muscle turbo clean (which by the way i noticed the effect a lot regarding power and willingness to rev,(when the car is normaly working, but didnt solve the problem)

Replaced EGT with new one.

 

Also i should mention i took it to a friend mecanic to check for codes and none showed up, the car was working fine that day though. dont know if they reset?

 

Any input much apreciated.

 

Ed

Edited 6 February, 201511 yr by edwardwaite

Diesel 4x4 was never offered in the UK, so we can't be 100% definitive.

 

Check the fuel system for an air leak.

Check the Mass Air Flow sensor by disconnecting it which puts you on a default airflow map. If the car runs smoother then replace the MAF.

When was the oil in the Haldex last changed? Haldex themselves recommend every 20_000 miles (32_000km).

+1 for MAF sensor.

Thanks for the replies, sorry i forgot to mention also tried the MAF sensor and when i disconect it the problem is still there! i disconect it while the engine is running, is this the right way to check?

 

Haldex oil has been changed, however i also should have mentioned i did pull the fuse to the haldex to make it front wheel drive only as i thought it might b rear diff, but problem is still there.

 

Could a fuel system air leak be intermitent? i was thinking it might be something electrical, faulty wheel speed sensor or injector?

 

thanks again

Rough idle could be unmetred air in the system, as you've checked MAF I'd be looking at pipe work next for splits or leaks.

if there was an air leak in the intake or indeed the fuel system, would this not be happenening all the time though? why would it fix it self by turning the ignition off and on?

So when you had it checked for codes did they use VCDS/Vagcom? If a generic diagnostic/code reader was used it's a different story as they often don't recognise all the VAG codes.

If recycling the ignition solves the problem then that suggests the ECU is going into limp mode so there should be fault codes logged.

Hey guys problem solved for anyone experiencing my issue, it turned out to be a faulty injector wire, car runs smooth as silk now! cheap fix also!

Glad you got it sorted buddy but i would have thought a fault code should have got logged there. A misfire or fault to that cylinder?