Got a S2 Escort turbo with a problem noticable on the motorway when accelerating in 4th or 5th gear. When i put my foot down the boost pressure rises and peaks at 18psi and holds at 16, if i continue to accelerate sometimes the engine will cut out (rev counter drops to zero/ignition cuts). If i release the accelerator then press again it will fire up and continue ith no problems.

Any ideas?

Cheers