I have a 1992 Escort Cosworth and intermintently when it comes up on boost it holds back, I have tried the actuator and wastegate, air temp sensor, hard wired in the two large multiplugs on the inner wing and changed the boost controller!! Can anyone give me any more ideas, its getting frustrating now. Its not miss firing just holding back!!

 

Take it to PE or Torque of the Devil, could save you £££ buying & swapping bits.

 

Has the timing been tampered with of late?

 

No timing hasnt been touched, it was stored through the winter for 6 months and has been playing up since, do you know where the main earth is for the car?? Im conviced its electrical as one minute its fine then holds back and then fine again.

 

Check the multiplugs on engine wirings, can make a lot of mess. I have cut them away on some Cosworths

 

Ive got rid of multi plugs and hard wired, have you heard of the fuel pressure regulator giving trouble on them before??

 

It could be, have you check your fuel pressure when you driving, it must follow up whit your boost pressure. A friend of mine, got problem whit blocked fuel pipe, got lean on lambda on boost. After try everything from twin fuel pump, changing regulator, changing fuel filter, whitout help. Then we try whit a fuel pipe, and it sort it out.
Something blocked the pipe when rising fuel pressure, boost going up, and fuel pressure down, could make a melt down engine

 

I have now disconnected the idle stabilizer and after several miles of spirited driving it has been faultless, what should I replace to solve this as the car must be intermmitently losing fuel pressure on boost, could the water temp sensor to the ECU affect this??

 

You should have a wideband lambda connected, to check how it is on different temp and boost. If the temp sensor is fault, it can result in lean on fuel, but it should be the same on and of boost.