Having some issues with my 04 wrx and i'm not really sure what to try next.
When accelerating enthusiastically out of a junction while turning right, the car bogs down, coughs, farts, etc etc. Its like its starved of fuel, air, both, **** knows, there is just no power at all. It sometimes comes back to life after letting off the throttle, other times it just cuts out. Start the car up again and its like nothing ever happened. No check engine lights, no stored codes, nothing.
I thought the fuel pump might be failing as it was getting louder, so change that for new. Same.

Noticed the lambda sensor wasn't monitoring so thought it must be that, replaced with new. Same. Although thats now monitoring so can't complain.

Checked the crankshaft sensor, covered in metallic dust/filings. Cleaned it all off. Same.

I was thinking failing MAF but surely it would have an issue constantly, not just while turning right????? I cleaned the maf last week.

I checked the knock sensor, seemed to be within tolerance.

The plugs were changed last year, nothing out the ordinary on the old ones.

I seafoamed the engine last year (if it actually does anything).

Checked for vacuum leaks.

I'm running out of ideas, and don't want to keep buying bits that might not be necessary. I someone else has had this problem please let me know what you tried/used to solve it.
It almost seems like the lateral g force is doing something

I know some will say not to put my foot down turning out of junctions, however sometimes its unavoidable due to pulling onto a main road everyday with a bend to the left so you can't see whats coming until its there. I don't like to hang about when i see people flying up behind me.

Any help would be greatly appreciated.

 

Does it still happen when u have a full tank of fuel or only when 1/4 full or below ??

 

Yes it still happens with a full tank of fuel

 

it is surging
fit a swirl port and it should sort it out

 

not to sound dumb, but what is a swirl port and whats it do?

 

Swirlpot is a small container of fuel somewhere in the car, normally boot or in the engine bay.

If your in-tank pump is starved of fuel due to surging, the small pot contains enough to keep fueling the injectors.

Intank Pump - Swirl Pot - External Pump - Injectors

I think it's unusual to get fuel surge on a full tank, but I get it consistently under hald tank on trackdays - but never on the road...

 

Ah I see. Without the swirl pot though on a track day, would it not surge in either direction?

I can't help but think it might be something electrical related.

Either way, I may have to try the swirl pot to eliminate that. I seem to think the engine starts it's cut out around the 3.5 - 4k rpm range, even when I have straightened the car up. it's difficult to explain.

 

The fuel tank has got a hump in the middle of it (transmission tunnel) and the pickup pump is on the right hand side of the tank, so occasionally you get a situation where you turn right quickly and the fuel sloshes over into the "other" half of the tank - which then stalls the pump for a few vital seconds.

Left turns are not bad, because the fuel surges in the "right" direction towards the pump.

I get it at Blyton Park all the time, back straight chicane goes left then quick jerk to the right. 3rd gear on entry, get the gas back on just as the car is turning into the right hand section and then out of the kink into 4th... BAM - fuel surge about 30-40meters down the road.

Never happens on a full tank.

Had it worst of all at Cadwell, double right hander at the top of the hill - car completely cut out and stalled at about 90mph...

Not good.

 

I had exact same issue. It was my fuel pump. Same thing, I was making a hard turn, and on the exit of it, or just about after I exited the turn my engine will start cutting in and out and make funny things, sometimes it was even stopping all together.

 

as you're on the road, slow the **** down

could try new fuel pump

 

well so far I haven't seen a sign in the middle of the roundabout to say "15mph" so all I do is go 40-30 or whatever else is the speedlimit

Yep. Just use any other fuel pump off from a friend or something. I was chasing my issue for months, gave up, put new bits for remap(including pump), hoping the new map will sort it out and boom no more problems.

Then new fuel pump died, put the old one back in, and I was back to the surging issue. Hence I knew my old fuel pump was causing the issues.

 

Mine was the aftermarket fuel regulator. Fit back the factory fuel regulator, all good for months now. Fuel pump was relatively new. Fuel relay change, same old story.