do i have a boost leak?
 

my cars been fine since ive had it,that is nearly 4 years now.
i got ot mapped and had the exhaust changed,im just waiting for a call toi get it mapped again.
over the last few days,when i take the revs round hard and it goes over 4000revs my car jolts a bit then goes then joltys again?
is this a boost leak?

Sounds more like overboost causing fuel cut, you shouldnt rev the card hard until it is remapped.

yeah i know not to rev it that hard till its mapped again,i havent,only a few times,it never used to do it though?

could also be an ignition related issue as well.

What year car is it? If it has the individual coil packs these do break down over time and cause a weaker spark which does cause issues around that kind of rev range (full boost)

Have you tried spraying carb cleaner through the boost solenoid? If that's gunked up, it would cause overboost.

It worked on my car, which felt like I was hitting a brick wall when the fuel cut kicked in :brickwall

had a similar sounding problem with mine, cured by cleaning the MAF sensor with
some brake cleaner and a cotton bud. works a treat now. IIRC it was the red bulb type thing on the MAF that was all gunked up. could be worth a try

its a classic 2000,its now having another remap on the 22nd of this month and they are going to do a diagnostic check at the same time so hopefully the problem will be sorted.

more air flow due to bigger zaust would put boost up maybe to the limit (whith it already being mapped and uped boost) and because weather is getting a little colder that little bit more boost may be taking it over the limit and fuel cutting when its mapped it should be fine
a blocked 2 port boost valve will not overboost it will just divert all air to the actuator...... but a blocked 3 port will cause fuel cut big time....

Isnt fuel cut like hitting a brickwall though and very noticable? He says juddering. sounds like maybe one of your plugs could be going. the gap is to big and as you run it hard on high boost the spark is to weak to ignite fuel and in effect you run on 3 cylinders. happened to me.

When mine was suffering from overboost, the effect would depend how it was being driven. If I feathered the loud pedal very gently, it was more of a hesitation. But any more than that and it felt like hitting a wall.

sorry it is more like hitting a wall than juddering

Sorry to jump in on the thread

I hit fuel cut once the other weekend in 4th gear never done it since but ever since i've owned the car i've always had hesitation i've changed the sensors people say could cause it (Maf & O2) still no joy, am i looking at the boost solenoid causing both probs hesitation (worse with a cold engine) and fuel cut?


Cheers.