2004 S60R AWD Stutters/Hiccups on Heavy Accel

[alexk243]

Just bought a 2004 Volvo S60R AWD and it seems to run great with some small issues I need to address (later), but the big one that bothers me is that on half throttle it goes great, but on 3/4-full throttle it seems to hiccup or stutter. My thought was fuel delivery, but I dont know enough about these cars to know where to start.

Any idea?

Seems to have a few additions to the car that may effect it. K&N Ram air intake, straight piped exhaust (way too loud... Code for O2 Sensor is on).

Thanks in advance guys

[JRL]

Well, first replace the 02 sensor(s), then remove that K&N and check the MAF. If you think the 02 code is from the straight pipe then you need a rear 02 spacer
K&Ns wipe out MAF sensors with their oil.
Install a new set of OEM plugs gapped to .028 and go from there.
Why would would post this without at least replacing what you KNOW is bad is beyond me!

[alexk243]

Well, first replace the 02 sensor(s), then remove that K&N and check the MAF. If you think the 02 code is from the straight pipe then you need a rear 02 spacer
K&Ns wipe out MAF sensors with their oil.
Install a new set of OEM plugs gapped to .028 and go from there.
Why would would post this without at least replacing what you KNOW is bad is beyond me!

Yeah I have heard about the K&N Filter oil issues, that being said it needs to be cleaned/re-oiled as well. Ill check the MAF in the process.

Almost positive the O2 code is from the straight pip/lack of a CAT... feel like the old owner removed it.

Well I didn't know what was bad... Didn't know that an O2 sensor effects honestly... wasn't sure if that would effect it or if it was just a nonsense code. Thats why I asked lol. Thank you for the help with that. Would a O2 spacer fix the running issue or just get rid of the code?

[alexk243]

Can anyone tell me if the O2 Spacer will fix the running issue or will it just remove the code?

Not to familiar with how that system works.