Just to add something, my car did the same thing as yours is doing. When I would start it up, it would run fine, normal a/f ratio's but very shortly after it would go extremely rich. Didn't throw a code for like 3 days

 

Hey man I think that I found your problem. I checked your log and what I thought was happening is. Scroll down to cell 812 and look at your o2 sensor voltage. It will drop completely to 0 and that is at 4700 rpm. I would have to say that its your 02 sensor that went bad.

 

Also check out cell 161-168, where the problem starts, 454 is another example, you might want to check the rear o2 as it the voltage drops off as well, cell 458 is an example of the rear sensor. This is just my .02, but that seems like the problem, hope it helps.

 

When I still had a stock MAF on my car. I used to always notice two things..

If my DV was partially open at idle, and recirculating, it would cause all sorts of idle problems.

Another possibility is as someone might have mentioned, some disruption of airflow due to the GT35r's surge ports..

If your MAF sensor is mounted in the stock manner (the top square facing up) try rotating it 90 degrees so the wiring harness connector is facing up..

Also, as a test, if your DV is opening at idle, disconnect and plug the vacuum line to the DV, see if the problem goes away. If it does, then you have a starting point to work from (increasing spring pressure in a DV)

I had this problem specifically with the stock and crushed 1g DV on the stock MAF running the first gen Buschur evo intake pipe.

 

yeah i also noticed that..and jack ill try flipping the maf and seeif it changes anything.....btw i dont have anti surge ports tho..



*edit*

tried flipping the maf and blocked off my bov and it made no difference

 

Any chance the screen in the maf has been compromised? It will definitely cause idle/fuel problems.

 

Oh yeh, thats actually a good point besides the obvious.

 

already checked the screen, its perfect...

ive spent hours trying to figure this out...nothing i do changes the rich idle dips at all...

i still think it has something to do with the maf.

i have a maf traslator and a gm maf sitting in my room i might throw on there sometime this week.

 

Maybe you'll get lucky and it will eventually throw a code, if it does turn out to be the o2 sensor hit up www.oxygensensors.com, like 80 bucks, much much cheaper than going through mitsu.

 

Can you at least try a different o2 sensor, or inspect the wiring harness to it..

when I installed my GT35r kit, I extended the length of the wiring harness to my O2 sensor so i wouldn't experience problems with the wires.

Another thought is if you removed the O2 sensor to swap it over using any sort of "shock" it could have become damaged. (Hammer to wrench, impact gun, etc..) We all know O2 sensors are a PITA to remove after they have been heat cycled a few times..

 

Always remove an O2 Sensor while the piping is still hot(engine off,duh), WAY easier to crack loose (in case this wasn't known).

 

just try to not burn the crap out of your hand doing it

 

im new to the forums but i saw this post and thought i could help with 20 grand under my hood and 310 whp. YES 310. how i dont know. anyway. fuel pressure regulator and fuel rails with a new tune should solve your problem.
ill try and update my parts list soon as i figure it out

 

Wow, most of us spent less than 2 grand and reached the 310whp mark. You poor, poor man. With your suggestion of adding more components under the hood rather than find the actual cause must explain the 20 grand I guess.

 

for 20 grand you could almost buy whole other car!

Any news from the OP?