I have just had a Forge recirc valve and spacer fitted to my car and after two days of it being on the check engine light has came on, so I wheat to my local garage and had it diagnosed and it came up with Turbo/Supercharger Under Boost I take it that this is caused from the Forge valve as I've never had an issue with the car until now? Any help on this matter would be appreciated. Thank you.

Also the engine has cut out twice on me which I'm very concerned about.

Check your other thread