wow. what a story. ive been trying to figure out this same exact problem and came up with NOTHING. Ive literally checked everything accept the 02 sensors being that the problem seems to not be that. Absolutely frustrating. especially with all the money i have in my motor.... completely built and turboed. the flat spot you've been talking about is not imagined as some people has suggested. Ive been trying over and over to get it tuned with various tuners and ECU's and all i can put down is a pitiful 285 WHP with 14 lbs of boost... fuel economy is terrible as well and i occasionally get codes p2a00 along with p0187 but mostly just p2a03 bank one sensor one range performance. Lately however ive been getting p0300 RMM which doesnt make sense because it is out of no where. It almost feels/sounds like the exhaust valves are not opening all the way or something, i notice that the AFRs are erratic sometimes lean and sometimes rich, tuned with Osiris now) there is a deffinate flat spot-sputtery sounding exhaust note and no power. at times it seems like it wants to go... but it dosent. i went to the extent of redoing the timing thinking it was that but does the exact same thing. now im leading towards it actually being the A/F sensors because ive checked everything else. the other few things that it may be as suggested by other is: bad ECU and or bad harness.

 

wow. what a story. ive been trying to figure out this same exact problem and came up with NOTHING. Ive literally checked everything accept the 02 sensors being that the problem seems to not be that. Absolutely frustrating. especially with all the money i have in my motor.... completely built and turboed. the flat spot you've been talking about is not imagined as some people has suggested. Ive been trying over and over to get it tuned with various tuners and ECU's and all i can put down is a pitiful 285 WHP with 14 lbs of boost... fuel economy is terrible as well and i occasionally get codes p2a00 along with p0187 but mostly just p2a03 bank one sensor one range performance. Lately however ive been getting p0300 RMM which doesnt make sense because it is out of no where. It almost feels/sounds like the exhaust valves are not opening all the way or something, i notice that the AFRs are erratic sometimes lean and sometimes rich, tuned with Osiris now) there is a deffinate flat spot-sputtery sounding exhaust note and no power. at times it seems like it wants to go... but it dosent. i went to the extent of redoing the timing thinking it was that but does the exact same thing. now im leading towards it actually being the A/F sensors because ive checked everything else. the other few things that it may be as suggested by other is: bad ECU and or bad harness.

 

Since the Crawfords went in I have had p2a00 & p2a03. They were in and it happened on the old motor so we looked at the headers and the 02 is sitting up out of the way of 2 of the pipes and right in the flow of one. The mechanic guessed possibly since it's mainly seeing only one it has insufficient flow causing a low warning. IDK but it is annoying to have a 100% new engine running great that has codes.

 

did anyone find a solution for this? I had a leak in my in drivers side cat but i'm getting the P2A03 code (other side). I haven't replaced my o2 sensors, as I want to rule out other possibilities. I will go back under and check for other leaks one more time today, in case I didn't catch something.

 

I was certain it was not the sensors but after I had made sure everything else was fine I replaced them. Over 1k miles & no code.

I went with OEM connector Densos from Amazon. They were about 160 for the pair.

 

This guy posted this in January, and didn't go back to that thread. So maybe it's worth a try?

 

I take it you mean just the rear (cat-section) O2 sensors?

 

Hey guys, I had the same issue (not as serious as the two main guys on this thread) I sealed my cat leak and poured some injector fluid and it turned off.

 

Yes.

 

Now that I'm back and able to test it, I did. I unplugged my rear O2 sensors and have since been unable to replicate the problem. I can now say with 95% certainty that they were, indeed the cause of my problem. Which is now fixed.

Thanks for posting your fix and giving me a bit more of a push in the right direction.

 

so have code p2a03 looking into the problem I have hooked up a ob2 scanner, it is reading that bank 1 and bank 2 both sensor 1 are not getting any voltage. Not going to lie I was in the ditch the other day, was not bad but the code came on after 100k after the accident. So I figured it hit some wiring but it all seems to check out. Im going to have to pull my headers just to examine for cracks I guess... Anyone else have other options? all wires are connected and the sensors dont seem to have taken damage. 08 350z