This experience shows the very occasional positive side of this trend, a chap rang me this week declaring his car was running unevenly and performing badly, he had been to a vauxhall main agent who did not carry out any diagnostics, but strangely advised replacing the crank sensor, the customer bought one and it was delivered to me with instructions to fit it.
Despite my suggestion to find out what was actually wrong he insisted Mr vauxhall must be right, so I fitted the sensor then showed him the siliconed up damage on the back of the inlet manifold.
OOOps, perhaps he should have googlfied his problem?
Phil!