BluestreamDE

Some bad news, yesterday my car started to struggle and die afterwards outta nowhere, once started, would shoot up to 3k rpm then struggle under 400rpm with my vaccum/boost gaige showing -5 to -2 (-20 is round normal) and AFR gauge showing really lean like 18 and up, until it stalls. Received three codes, P0102, P0123 and P0223. Car was fine with no issues until this happened. I replaced the throttle body with an older OEM one and no change, changed spark plugs, cleaned maf sensor, changed out o2 upstream sensors, checked fuel pump, cleaned injectors, getting pressure with the fuel system at 48psi with the 320lph and no fuel return system. Problem still persists. Today car will not turn over, i took out the spark plugs and saw they were soaked in fuel.

My last idea would be the the wiring harness or coilpacks, or possible clogged HFCs as they may cause the back pressure that maybe present due to the low vacuum. Gonna be searching the forum for folks with similar issues and see if they had a solution Any ideas where to look would be appreciated.

BluestreamDE

Attempted to do the coilpacks as I had spares, after swapping them out, there was no change. Also to add, I am unable to perform the throttle/idle relearn procedure untill the car is of normal operating temps because I can't keep the car running, so I am stuck between a rock and a hard place.

Spike100

Question... How (What device did you use.) did you acquire the codes?

I think your problem is based in a vacuum failure.

--Spike

BluestreamDE

I pulled the codes thru the ROM editor software by UpRev.

Perhaps, so what I did was unplugged the battery from the car for about two hrs and it started right up, but idle still fluctuates at 400-1200rpm with -16 to-21 vaccum, high AFR at around 20.0 up to almost 60.0 when it bogs low then picks back up to 19-20.0 afr. Short term trim on both banks are pegged at 25.0, when I unplug the maf it pegs -25. I'm assuming O2s are bad? My tune has not changed and is the same.

BluestreamDE

Today I reinstalled the previous upstream o2 sensors, performed the Throttle relearn procedure and it started back up and is idling within parameters of my tune from a cold start at 1000rpm. Only issue now is that I am still running verrrry lean at 18.0 and up to almost 50.0 AFR. Exhaust pipes are insanely hot just running the car for 3 minutes. Short term fuel trims still around 22-25 in both banks. I checked for exhaust leaks with a water bottle and found none. My guess now is that the high flow cats I have are fubar? Or maybe downstream o2s also need replacing?

BluestreamDE

Did an Idle data log ( Attached below ) a few minutes ago to see more detailed information with my rom editor software and recorded when I purposely made a vacuum leak loosening the coupler clamp after the MAF housing to the throttle body and It ran almost perfectly with afr at 14.1 up to 16 and healthy vaccum of -21, waay better than the last time running from 20.0 afr and up, Idle stayed around 1000-1200rpm during the time I made the leak, but once I secured it back and tightened the coupler everything went south, AFR was at 25.0 and up and had rough idle. I did notice my down stream voltage looked weird. Perhaps I was right about the downstream sensors going bad. After the exhaust cools off some I will switch out the post cat o2s with an old set and see If the car changes its behavior.

Dali84

I know this is a dead post but did you ever get this sorted mate? I have the exact same issue in my z. Thanks

jhc

Unstable idle and performance = severe vacuum leak. Easy to diagnose with a vacuum guage.

Dali84

so i decided to do a basic check today and I disconnected the crank sensor, the car started after some time and was running well, it had a slight miss. What this tells me is that the guy that did the engine swap missaligned the flywheel and the timing is of. There is no vacuume leake, this was checked thoroughly.