Hi I am new to the site, can anyone help me with two fault codes on my 2001 Skoda Octavia vRS. These are:

17939 P1531 Camshaft Control Circuit open (intermittent)

17544 P1136 Long Term Fuel Trim Add.Fuel,Bank1 System too Lean

Car seems to run ok, but occasionally has a moment’s hesitancy.

Car pulls without problem under heavy throttle.

Thanks, Dave.

Clear the intermittent fault and see if it comes back. The 17544 is likely to be the symptom of the fault. It looks to me like it is lean at tickover (that's what the Add. means) when the vacuum in the inlet manifold is used to get the air into the cylinders. Too lean - then I would suspect that the vacuum is causing extra (unmetered) air to be drawn in through somewhere. The likely culprit is the breather hose to the passenger side of the dipstick, it is quite well documented on this site. If you move the hoses (carefully) with the engine running you may well hear a hissing sound as the air is sucked in.

I will try what you suggest, thank you.