Hi everyone,

 

I'm fairly new to the Smax 2.5T I have a 2008 model that's decatted, has a Ram air pro filter , block mod has been done, head gasket set fitted, cambelt changed, water pump changed and it's had a live Dyno remap resulting in 278bhp.

 

Ive had it since 2023, since that time it has sometimes had a violent judder on hard acceleration where the engine feels like all fuel has been cut off for a second or 2 and then comes back to life quite violently, this was only under hard acceleration like foot to the floor. Now I had a code on forscan this morning relating to running lean. 

 

I have also noticed that sometimes the brake pedal goes a little soft while driving hard after a hard boost from the turbo.

 

I am just curious as to wether the performance issue and brake pedal feel changing could be a vacuum related issue and where to start looking if anyone else has experienced this ? Or if there are any common faults that would cause this. Forscan used to give me an error relating to fuel pump circuit but that doesn't appear anymore... 

 

I was going to start with fuel filter and check all vacuum hoses and boost pipes. 

 

Anyone who knows this to be a common fault I would appreciate any light shed on it.

 

I have changed the boost solenoid behind the drivers wheel already for a new peirburg one. 

 

Thanks everyone!

 

James 

With all of that change from Ford standard spec, what do the dyno people say as it sounds like a fuelling issue and the remapping may need attention (assume it's petrol otherwise I'd still say change the fuel filter)

Any hint of issues affecting braking need urgent attention IMHO which sounds vacuum system related?

You seem to be starting in the right direction so come back after the basics?

However as its neither diesel or standard it's out of my ballpark!