SPRAYED 01

iTrader: (22)

Car is fully tuned for a few years with no tuning issues. Same setup for years to. Out of the blue I will start it up and it stays around 11.3 to 11.7 afr, idling cruising doesn't matter. I go wot and it goes off the charts rich.
This happens about 1 out of 10 drives. Most times it runs perfect at 15.0 afr idle cruise and 11.5 wot.

SPRAYED 01

iTrader: (22)

Some times I will drive for 30 mins of the high way and eventually it will just right to 14.7 - 15 afr out of no where. Other times it stays rich for the whole ride, i park it come back a couple hours later and it runs perfect. Most times it just runs perfect.

Sleeperls

Notice any power loss. What wideband and you using and how old is the sensor.

SPRAYED 01

iTrader: (22)

Yes it Does seem to run worse when its super rich, pulls less vacum at idle too. Aem uego, 6 month old sensor.

samdogmx

iTrader: (14)

have you tried swapping a new 02? if its not 02 sensor/s kinda sounds like an injector is hanging open.

SPRAYED 01

iTrader: (22)

I was thinking 02 since they are about 4 years old but it happens at wot too. Its not looking at them at wot. It could be an injector. They are 4 years old with about 10k miles

SPRAYED 01

iTrader: (22)

I do have meth injection but it does it even with the kit off.

Forcefed86

iTrader: (4)

I'd try another sensor... 3-4 years is about all the bosch LSU sensors are good for. Many times less depending on the type of gas and placement in the down pipe... Mine usually don't last that long anyway. Have you tried a timed "free air" calibration/test?

SPRAYED 01

iTrader: (22)

The wide band is 6 months, the narrow bands are 4 years old.

123quattro

Maybe a restriction on the fuel return line?

SPRAYED 01

iTrader: (22)

I guess it could be a restriction but it feels electrical due to the fact its intermittent.

ddnspider

iTrader: (26)

Any correlation with your fuel level? Do you run more than 1 pump? You should be able to log o2's assuming your closed loop to verify you're going pig rich.log spark too and see if it drops out.

edwardzracing

iTrader: (59)

Might a faulty IAT sensor have something to do with it? Not too pricey of a part to replace just for the hell of it.

stevieturbo

logging, logging and more logging.

Then look for the problem. It should reveal all.

And are both banks rich ? does the narrowband also correspond as rich ?

SPRAYED 01

iTrader: (22)

I do run 2 pumps, one all the time the other kicks in @ 5psi. I will do bunch of logging.

RonSSNova

iTrader: (3)

High fuel pressure would make it go rich

LASTLS1

iTrader: (7)

Really sounds like a sensor.