Audi A4 non start problems(intermittant)

[WestgateMotors]

We are a small independant garage down south and have got an A4 that we have chasing an intermittant non start problem for ages. Sods law every time we get hold of the vehicle it doesn't seem a problem. The owner hasn't got to go far before it happens. We have only experienced the problem once and managed to check the fuel pressures, they were o.k.,and then it started, so we were unable to continue checking. We have renewed the TDC sensor as a matter of course, we have code read the vehicle and the only realy relevant engine code that came up was cylinder 1 reference (camshaft sensor) which we have replaced. The other code that comes up each time no matter what the engine is doing is an immobiliser code.
Question;Do you know if the immobiliser readers(aerial) around the ignition switch give problems? We have tried both keys.

[Lofty79]

Yes they are a pain in the *** mate, immobiliser spasmodic fauld, between transponder in key and car itself. Cant say as i know a solution but it is a common fault, i disconnected the battery overnight and a week on and it hasent done it again.