Hi, having recently had a number of issues with this car my wife today said the glow plug light was flashing but only for 10seconds. The car had recently braked and after searching this I've checked the

Brake lights work, they do. On and off with pedal. So I guess it is not the brake switch

I've read that the MAF sensor following air filter could be faulty. Just changed this as idle reading was dodgy and was trying to fine out cause of poor fuel economy. Its done 200 plus miles not done this straight away

Egr was replaced which was blocked but this was 1000 miles ago. Also there are on sensor on this, it's a vacuum line to it only

Don't think it is this

Recently at weekend both rear brake calipers have been changed. There are no leaks and brake fluid level is fine.

This solved the poor fuel economy and brakes are better also. Both rear brakes were bled and caliper were filled with brake fluid before fitting.

Car has bulb failure light which has not illuminated. Led top brake lights are working also with the two working brake bulbs. One brake bulb was replaced 10k ish ago. The other is probably due Any ideas?

With out a proper fault code scan using VCDS it is just guesswork as any number of separate faults could cause this.

 

You could have a duff battery, duff glowplug, duff earth strap etc etc.....

Could still be the brake light switch as it has two circuits one for the brake lights and the other for engine electronics. If you have cruise control does it disengage randomly? I had that issue and it was the brake light switch athough the lights were working.

Follow up...

Brake pedal switch needed replacing. See DIY guide on this site. Very useful. 

Local Indy confirmed this.