HOW AN YOU TELL IF A FUEL PUMP IS BAD OR A O2 SENSOR???

well here is my problem my car can start sometimes but only idling.. but when i press gas it dies,,, or sometimes it will start then dies right after or doesn't start after dieing...???

can nayone help me solve my problem so i can not be to owrried.. thanx..

email me at iik9ii@hotmail.com or call me at (808)280-5523 if you know answers because i only go on i-club once in awhile because i am somethimes buzy but thanx... and name is kevin

 

Any CELs??

Is your car modded? if so what mods?

 

only get catback>>> i might think o2 but like i explAINED it does when i press gas aFTER LETTING IT IDLE THEN CAN'T START AFTER... THE IDLE JUST DIES WHEN I PUT GAS TO IT....



HELP PEOPLE PLEASE

 

so what guys no help at all

 

bump

 

Put a fuel pressure gauge to it. I haven't got the specific fuel pressure specs for the 06 STi, but on my 04 its from 41-46psi. In some cases you might have enough fuel pressure to idle but once you step on it the fuel demand becomes greater and if the pressure is too low it won't have enough to keep the engine going.

On OBD II cars like ours the PCM keeps track of the O2S readings and checks it for range and switching time, if it is bad then it will illuminate the check engine light.

If you have access to a digital storage oscilloscope (DSO), you can connect it to the O2 sensor, it should read from .1v - .9v in a sine wave pattern, and go from the highest point to the lowest point at around 100ms.

 

sounds to me like a dying fuel pump or a clogged fuel filter. I had a very similar problem where whenever i try to gas the car it would bog down and not run very well (like it is going to die) also sometimes the car would not idle at all. So I replaced my fuel pump/fuel filter and it works fine now but i'm running lean so i changed out the injectors and it works better but i still kind of feel a lag whenever i go from 2.5k-3k rpm.