Turbo BS Thread

I need some help fellas. I'll be posting this on more than one thread (thanks in advance Josh and everyone else)
My truck has been running lean in closed loop lately... like 17:1 and even leaner. Under 55mph it seems to be normal, but at highway speeds it slowly starts to revert to running lean (fluctuate from 15:1 to sometimes 20:1). Also when I come to a stop and put it in neutral, the truck will idle very low at 17:1 or leaner, then (usually) gradually go back up to 800RPM at 15ish:1 AFR within 10 seconds. WOT is PERFECT 11.5:1 AFR and very powerful (14-18 degrees timing advance depending on outside temp).
The weird thing is that my OBDII reader is telling me that the O2 thinks that I'm running rich (I think). I have no cat, and ZERO rear o2 manipulation, and the readings tend to vary A LOT between the two sensors. When it goes lean, the scanner says that the front O2 reads ".500+" and the rear will read ".200 or lower". LTFT will sometimes be up to "-15". I had a year old denso o2 that I swapped for a boshe (yeah yeah I know) to see if the denso was bad, but nothing changed. No intake leaks, no FPR leaks.
I have cleaned the MAF and it's inner wires to a mirror shine. I have cleaned the connectors for the MAF and the front O2 and applied dielectric grease.
Oh... and no codes.
If I turn the engine off and back on quick (while driving), it will run perfectly for a couple minutes.
Also, I know that when engine braking (MT), the ECU is supposed to cut the fuel which should result in maximum lean readings on the wideband... but my AFR's are 10:1-13:1 while engine braking.
I really need some advice because I have serious problems with not only running lean, but taking my truck in for something that is probably easy to fix.

 

This is similar to what iv been going through but ran a little too much leaded racing fuel and im pretty sure i ruined my bank 1 o2 sensor

 

Yup, lead will definitely mess up the o2. Why didn't you just use e85? I've run up to 50% ethanol and my truck runs beautifully

 

You could try a new O2 sensor. But if it was the sensor, you should see a code. Other than that, not sure.

 

Where do i get E85 ?

 

Mapco has it right by my work... but usually every other town or so has a gas station that has it (at least in Alabama)

 

oh but it takes about 30% more fuel to burn e85 so your injectors may be a bit under sized, might wanna double check and make sure your injectors are at least 50% larger than stock before you fill up with it

 

Yeah I don't think I have the right injectors plus I don't know where they have it here in Texas

 

Yup... I had to turn up the meth when running e85, but it just runs so much better.
No more than half ethanol total concentration though, because gasoline fuel pumps are designed for the gasoline to lubricate the pump as it works. I also added 6oz of Lucas fuel stabilizer every time I ran e85 for extra lubricity.

 

I already bought a brand new boshe (I was desperate) and there was no change at all whatsoever. I think I might just order a new MAF and see where that takes me. Every time I clean it, it gets a little better... but still

 

Mine is starting to die when I'm driving and I let off the gas at 20 mph I wonder if the fuel pump got messed up from the leaded gas and or if I need to replace my map sensor too

 

I'm curious if my maf is going out too. It's old and had to put up with a nasty k&n oiled air filter for 7 years

 

Mine is the original 17yrs

 

@GioGuitarDude

Give your fuel system a clean. Fuel filter, injectors, maybe flush your fuel lines(force your fuel pump on when discharging fuel into a bucket etc). I'm suspect of the injectors. At least that's where I would start

 

I don't think it's the fuel system but I'll definitely clean it out.
My injectors, pump (250lph walboro) and fuel filter are no more than 3 years old. I use fuel stabilizer almost every tank. It's really annoying trying to take super good care of your vehicle and stupid crap like this happens

 

Yeah I'm really starting to think it's my MAF. There is only so much you can clean. I heard the micro pores within the bulb and sensing wires in the MAF get plugged with excessive dirt and oil, and spraying it can only remove so much debris. I'll look for a replacement and get back to you guys.

 

It's definitely a fuel delivery problem.

If you take care of your fuel system, I would look into the maf like the others are saying

 

Whaaaaa?

 

Oh yeah.. my truck runs WONDERFLY with 5 gallons of e85. Only reason I don't do it all the time is because I hate filling up so often and replenishing the methanol (since I have to increase meth spray to keep AFR's down.

 

Wondering if my fuel filter needs replaced? 193k miles. Not even sure where it's at on the 3.4L