I had a 1.6i Mk4 Astra which had to have a replacement egr valve at about 58000 miles. This lasted about 10 months until it started to go seriously wrong and the car would keep cutting out and running really roughly. It was an intermittent problem but the car would often cut out and I got so sick of it that, one evening after a particularly bad journey, I made sure the valve was closed and then I disconnected it. It meant that I had to drive the car with the warning light illuminated all the time but I just put a bit of tape over it so I couldn't see it.
The car went on to do another 60000 miles with the valve disconnected and never missed a beat. It passed 3 MOTs with no mention of emission problems and the fuel consumption was totally unaffected.
When it came to selling the car I took it to the main Vauxhall dealer and got them to program out the egr so that the light would go out - this cost me £35 (in April 2009).
I now have a Mk5 Astra and guess what? That damn light has started to come on on this car! I am booking it in with the main dealer to have the egr programmed out as it is not worth replacing at £60 a pop when you can solve all the current (and future) egr problems for about £40.
Astrafan
June 2010