I have a IX GSR.....50k miles. I posted before about a loss in boost. Im about to just take it into the dealership but really dont want to, for $$$ reasons...As of now I have performed a boost leak test, and passed. I have checked the turbo...good working order spins freely. after motor is turned off the turbine continues to spin for a minute or so. vacuum lines are good. Basically i am boosting 0 and when im going up a hill or put heavy load then the car starts to jerk like its starving for fuel or air. the only code im throwing is a P0420 catalyst code. Ive had this code long before the issue arose....Im leaning toward fuel pump maybe?.?.? again zero boost and under heavy load or up a hill the car shutters and shakes when gas is floored. idles smooth, no oil leaks or any other obvious problem. please help!!

 

check spark plugs for contamination/proper gap. exhaust restriction could be another option, although there would be a lack of power. fuel pressure could be something to look into. maybe even bad turbo. have a shop do a diag. you don't have to let them fix it. more info please. weird!

 

u on original spark plugs?

 

u would be suprise what a boost leask test wont find.

 

intercooler pipe, fuel, did you switch any lines around, check to make sure none fell off, I mean you have to look into it a little, could be lots of stuff

 

Dang, like literally zero psi? Not even wastegate pressure of ~10psi?

 

Maybe your WG flapper door broke off and is now lodged in your cat. Seen it a few times before. More common with a dual WG port. Did some of the IX turbos have this? Purely speculation tho but it could explain why you can't build boost.

If it were a fuel pump problem your car wouldn't start. Pumps are kinda just on/off parts. They generally don't gradually go bad, just the filters get clogged. When they go out they just go out.

 

boost test is good....i just today put new spark plugs in with proper gap of .024. turbo is in great working order....again only code imthrowin is P0420 for my cat, but that has happened far before my issue. im leaning towards a fuel pump. after plugs the car still jerks excessively when floored. fuel pump????? maybe??? last thing ill change before dealership

 

you running stock intake box? if you are do you have the snorkel fastened to the rad support? also sounds dum make sure the maf is plugged in

 

The intake is INJEN, Ive had it on for 2 years without incident, and the filter has been cleaned every 6 months. the Maf is plugged in, and it is clean as well. great responses!! I like the outside of the box ideas. Im tryin everything that is brought to my attention. thanks, keep the ideas comin!

 

oh and i failed to mention that when I i go WOT it makes a deep rumble, almost sounding like an STi. then jerking starts at higher RPMs when im on the gas.

 

sounds like ur spark plugs change them out... do u have a wideband? if so what are your AFR's on WOT

 

Just changed out spark plugs yesterday with OEM NGKs. I dont have a way to read my AFR.

 

did u check for shaft play in the turbo and u made sure the plugs were gapped correctly?

 

no shaft play. turbo is in great condition, spins freely and the turbine has no knicks or flaws. gapped the plugs to .024 which is stock. i may remove my whole exhaust and see if something is bocking it up creating too much back pressure. the exhaust tone and sudden lack of power may suggest blockage. When WOT the car feels like it wants to spool but then just hesitates. its like its not breathing.