Hi
I seem to have an intermittent over boost problem on my 1990 RS turbo
The car has a ‘Collins’ chipped ECU and -31 garrett actuator and in the main the boost peaks at around 1.1 bar, holds around a bar before dropping to around 0.6 bar
Occasionally this peaks around 1.8 bar and the ECU appears to cut out and the boost drop. This generally appears to happen in 2nd or 3rd gear when the engine is under load but not when starting from stationary in 1st and putting your foot down.

Anyone any ideas??