Hi,
I have a Mk3 Cabrio with the 8valve 2l AGG engine in it.
The car has gradually developed a missfire over the last few months with a rough tick over, hesitation/hiccups around 2-3k rpm that seem to get worse if you are pushing it.
It failed to start the other day that was down to the coil pack that I've replaced with a genuine one.
I have heard about issues with the throttle body so have stripped and cleaned the throttle body and the crankase breather system.
I have checked the plugs and they are fine. The plugs, leads, distributor cap and rotor arm were all replaced around 10k miles ago, all genuine parts and they all look fine.
I have also checked and cleaned the air mass sensor in the inlet pipework, but that hasn't helped.
I have tried a basic lite version of VCDS and it pointed to a llambda probe issue - it may have been an old code, but just to be sure have fitted a new 3rd party generic replacement.
Replacing the llamda probe has smoothed things out a bit and made it a little flatter, but we still have the rough idle and hiccups around 2-3k rpm.
I have only just got the VCDS code reader so haven't had a chance to get to grips with it. I have managed to acquire a full version and will try to do some more digging with that, but aren't sure how much info I can get from it or testing I can do.
So, do any of you have any further suggestions?
Rather than going through all the other main sensors and just replacing them is there a way to go through and test them via VCDS or by testing resistances, etc?
Any help would be appreciated.
Thanks in advance.
Julian
