1JZ Random Rich/Lean

[Press22]

Ok so I desperately need help... spent a ton guessing already and problem is still here......


1JZ-GTE stock
62-62 Driftmotion Single Turbo
PLX Wideband
Stock injectors
Walbro 255

Problem is that USUALLY the car goes rich, while driving or sometimes at idle.
When driving and trying to maintain speed it can sometimes go lean too. Usually around 25mph but it can vary.
There is a random idle surge for a few seconds where AFR goes from 14.7 to lean. This goes away after a 10 seconds or so.

What I've done so far:
Installed AEM v2 and got it tuned
Installed Aeromotive AFPR (currently set around 38psi)
New Spark plugs (may or may not be fouled from it running randomly rich) BRK7
New Coil Packs
New Coil Pack Clips

My thoughts:
Possible injector clips being too loose, will replace next
Fuel pump acting up? Doubtful but possible
Sticky injectors


please help me out... already spent a lot trying to fix it.

 

[hvyman]

Sounds like tune issues.

What are you using for a idle valve or are you not?

 

[Press22]

Sounds like tune issues.

What are you using for a idle valve or are you not?

Should be just stock. Wanted to add the car did run fine before these problems started happening. Even on the Stock ECU it would drive ok.
Now the problem happens both on stock ecu and AEM

 

[f00g00]

Does it happen around 3000 rpm consistently?

 

[Press22]

Does it happen around 3000 rpm consistently?

I don't have a tach unfortunately. The only time I'd say I notice it around 3000rpm is in 5th on the highway.
Seems to be at any RPM if you ask me though

 

[hvyman]

You check for codes with the stock ecu?

Are you still using the fuel pump resistor?

 

[Press22]

You check for codes with the stock ecu?

Are you still using the fuel pump resistor?

No never checked for codes on the stock ecu.
Fuel pump is getting 12v

 

[f00g00]

The fuel pump has two modes of operation with the stock ecu. I have never run an AEM so I'm not sure if it operates the FP relay the same. You can test the voltage on the check engine connector and see if its 9 or 12 volts. The Walbros do not like running at 9V apparently.
You can read about the 12V mod operation here and see the theory of why it is done.
http://mkiv.com/techarticles/12v_mod/12v_mod.htm
Other people have had problems with lean spikes after removing the pulse dampener from their stock fuel rail but with the Aeromotive it is supposed to come off.

 

[Press22]

The pump receives 12v and I verified this.
I changed the FPR to an Aeromotive in hopes to fix the problem, didn't get any better or worse.

I uploaded a video of the idle hunt. Couple of people said to try a new o2 sensor so I may do that next.
https://www.youtube.com/watch?v=9RKp-71xH7M&feature=youtu.be