Help - S3 random surging no fault codes

[Gordie_S3]

Hey guys,

I recently scanned my S3 and found that the pre-cat oxygen sensor was faulty and I replaced it with a new one. Shortly after replacing it iv noticed my s3 would 'surge' or cut out randomly through out the revs while driving.

No fault codes either when I scan it.

Could it be something with the fuel? Fuel filter....fuel pump...injectors?

Thanks in advanced guys!

(Details of car: AMK, V3 CAI Badger5, N249 bypass, Forge splitter)

G

 

[s3dave]

Check your Fuel pressure reg for a blockage...

 

[Gordie_S3]

Put a new one in, its a bit better but the surge cut off still seems to be there. Its lacking on power aswell

 

[Gordie_S3]

So after a day of driving, no differences with new FPR.

Symtoms are more like hiccups/ fuel cut when I put the throttle down. N75 valve? But it would throw a code if it was faulty?

 

[Gordie_S3]

Went into this a little more as its gotten really annoying and I need to get it sorted before the tune...so I put a new fuel filter, re-tensioned knock sensors, new plugs, new MAF, checked boost leaks, couldn't see any vac leaks or hear, no bursts PCV pipes.

Only fault codes that come up are..

17524 - Oxygen (Lambda) sensor heating, b1 s1
P1116 - 35-00 - open circuit
17511 - Oxygen (Lambda) sensor heating, b1 s1
P1103 - 25-00 Performance too low

The replacement oxygen sensor I put in wasn't a Bosch unit and it was doing the same symtoms (hesitating, misfiring etc). I bought the exact Bosch replacement, but I have to wait for it till it comes from the states. Could it initially be this? It still throws readings threw logs.

Ive done a few logs and the ecu isn't pulling any timing either...