gtir boost problem, help needed asap

[gtirtrack]

right guys only had my gtir for a week now, when i first picked it up it was quick as **** in any gear scared the shit out of me, its running 340bhp and 310ft lb torque, my journey home from pickin it up was motorway miles and i was amazed at the 5th gear acceleration.
all seems to have gone a bit pear shaped. basically it just dont feel right, it doesnt seem to pull anywhere near as hard any more, especilly in 5t gear for example.
this is what i have noticed
seems quieter, exhaust
dump valve doesnt make as much noise when i lift off as if there aint much boost there
boost doesnt kick u in the back so much
lots of popping when lifting off,
also popping under accleration, like a misfire, not smooth power delivery,
turbo is very laggy, only a small t28 hybrid and dont really give good boost under 3500 at all, full stride by 4500 i would say, used to spool a lot quicker.
lame accelaration in 4th and 5th gear.
also boost sometimes builds up slowly and then a huge surge in boost then it all dissapeers again lol.
another mai concern is i have noticed it is absolutley drinking fuel. put in a full tank of optimax and it got me 150miles, with not much fast driving at all due to my work being close so engine dont have the time to warm up and also wet wether and the fact that cos it aint goin very fast i dont bother drivin i hard. i cant belive 150miles to 50quids petrol.
should i stop drivin it as i cannot afford to rebuild th engine if it goes pop as it has a full rebuild, forged be at cost of around 8k 5000 miles ago.
pls help me as its doin my head in a week into ownership. should i just get it looked at by a specailist, who will have a look in the surrey area.
cheers for all your help. nick j

 

[KF79GTIR]

Check all your boost pipes load of diagrams and pics in the how to and the problem sections in the search options also check your turbo and maifold nuts and gaskets to make sure nothing has come loose anymore ideas people?

 

[pulsarboby]

as kev said above really, check all obvious stuff, air leaks etc.
but if no joy, then would do a fault code check to establish any sensor faults etc, before you go any further with it!

 

[Fazz]

does sound kinda like aboost leak... all be it a small one.

Have you not got a Boost controller/gauge that you can monitor and see when and how much boost is being generated?

Sounds like a small ignition/fuel/boost leak problem.
Unfortunately a process of trial and error, a error code check may help thou.

Hope its not serious mate, don't think it is.

 

[steven_c]

check intercooler i had that on one of mine dump valve hardly work and ended up been intercooler leak