car:2006 evo IX 5 spd,
ok basically my car threw a p2195 code, replaced with new o2 sensor, damaged somehow threw p0134, replaced with bosch OEM by shop, even fixed my rough running idle and scaled injectors, took car for test drive ran awesome. Drove home threw p0134 again, erased, day later at start up and had bad real bad rpm surge almost died then threw p0171 code.

Over last 5 days it has thrown both codes randomly at least twice each but have not seen them at same time. I have physically checked all hoses and lines for looseness or damage, CLEANED the MAF, IAC and throttle body, set fuel pressure to book settings, used smoke machine to check for air leaks. disconected battery once while fixing battery connector.

As of this post car is parked and these are the issues/symptoms. Car runs like *** with rough idle, on start up after sitting a while it will do a bad rpm surge 3-6 times regardless of how cold or warm it is outside. Keeps throwing random P0134 or p0171 codes but never both at same time and 4 days ago one p0500 code VSS code, but has not appeared again just the other two codes. if i shift in to N and let rpms drop they go to stock idle but will jump to 1500 or so one time. My A/F gauge says im staying lean at 14.9, it does not drop below this even when im giving it gas. im using a slightly outdated snap-on ethos it only goes up to vehicle year 2005

i have been told my MAF is bad, a bad cat can cause this code, a bad IAC, a bad connector or connection, car needs time to relearn new o2sensor / tune. I have not the money to waste on pointless guesses any help would be great please and thank you, i cant believe that 2 sensors would be bad, one mayb but two

mods are AMS large fuel rail, detchwerks 880cc injectors, walbro 255, FP red 80mm, AMS full FMIC kit, GSC s-1 268 cams, fuel lab FPR, K&N Cone filter

 

i feel your pain, i was having the same 1st half of your issues, except i was running rich as hell, instead of the bosch o2 sensor i bought the denzo o2 sensor and didn't have to splice the wires, unfortunatley i started on my new build and figured id end up hopefully fixing the issue as i rebuilt my engine from the bottom up, i will be subscribed to this thread to see hopefully you get a final answer, good luck brother.

 

the BOSCH in there now is the OEM one has the connector and all didnt have to splice

 

Anyone? im really stumped, cant figure out whats causing crazy idle surge on start up and why i get the random p0134 code

 

Bump anyone please the dealership wants to sell me another o2 sensor but I'm not sure if its even the sensor all I get is a p0134 code

 

well too add my 0.02 when you said you check the couplers....did you do a boost leak test, becuz if im not mistaken the p0134 code can come up for a couple reasons, 1)one can come up due to faulty 02 sensor which you did replace, 2) could come up because your running like **** because you have a boost leak, 3) can come up because of an exhaust leak, which you did a smoke test so that wouldve verified it..i would say look at your map if you can check your fuel trims, check your volts and latency, you might have somethin simple as that causing your problems, id say try replacing or swapping your IAC valve with someone else and see if it gets better.

 

yea thanks, yea im getting a multimeter this weekend and a friends going to test the electrical for me to see whats going on at the o2 sensor connector, ill redo the smoke test on tue when i get back to school, and the shop that does my tunning said he will take a look at the tune and fuel trim. I am also switching out the IAC with my friends brand new one this weekend, but thanks for the info and ill make sure an write back what i found out.

I fixed the other issues now i just got the random p0134 code and really bad idle surge on start up or after its been sitting awhile, which id assume would be the IAC

 

Did you replace both the front and rear O2 sensors? When my front one went bad it caused some problems running and idling.

 

no just the front one, (b1 s1) its the only one i was getting a code for, im thinking its a electrical issue with the o2 harness, going to test the connection later on if i can find the connector diagram

 

Ok so, its been a few months and my car has been sitting in the garage, finally got the money totake it back to the shop to have them look at it. They said my ECM was "frozen" and they reset it and it took care of the p0134 code, so i drove it home fine np, drove it to school the next day np, at the end of school started car up and let it warm up, got in an CEL was on, used a snap-on scan tool and got code p2195 o2 sensor stuck. Now its a brand new o2 sensor and im thinking it might have something to do with the tune. ANYONE have any input? I havent noticed any difference in how the car drives, i only use 92-93 octance gas also

Running 880 injectors and a FP red Turbo

 

well my guess, to start shouldnt have that many broken 02 sensors in a roll start testing the wiring from where the 02 sensor connector starts, and check the wiring...that would be my guess....good luck u sure no exhaust leaks??? from mani to head? turbo to mani??

 

I did a smoke test on it and found no vacuum leaks, before i was getting a po134 code, oneof the local respectable tune shops said it was becuase my ECM was "frozen" so he reset everything and it was all good drove it all the way home np, didnt get a CEL code until today but this time its the p2195 code sometimes accompanied by a p0171 system to lean code. used a snap on scan tool and the voltage to o2 sensor is fine. Ill double check all connectors and redo smoke test as well. My question is could it be something with the tune thats causing these new codes?

 

get some eletrical cleaner, and spray the inside of all the connectors to clean up any corrosion or anything built up in it...

 

we did do that there was some white looking corrosion or buildup that we got out of the connectors but they are clean now, the voltage to the o2 sensor is within range just for some reason it just throws those two codes, if i wipe them out i can drive 1 mile or 30 before it comes back on. using the ethos scan tool the car appears to be running fine nothing out of the ordinary.

 

so think i have discovered the root of my recent issues, apparantly some how i told my tuner i had denso 880 injectors but i infact have detschwerk 880 injectos so the scaling and latency were way off. Totally my fault