Bank 1 Rich Bank 2 Is Perfect

I'm sad to see no one has offered any advice.

My at has a similar issue. It's actually a 96 with a pi swap as well. (What a coincidence)
I recently bought a bama x4 tuner for my car. It has a built in af ratio gauge. I noticed on it that occasionally the right bank will run rich for a bit. Then it will go back to normal. If I rev the motor while it does this, then it puts it back to normal as well.

I believe what this is is a dirty fuel system. My motor has 100k miles on it now. But my car has 200k. Fuel lines, filter, pump, injectors. These things gum up and get dirty over time and heavy use.

Try using a fuel system cleaner. Personally I'd go with a bottle of the B12 chemtool. Put that in the tank, give your motor the "Italian tune up" and let that stuff do its job. It cost $3 a bottle. Not a big risk if it doesn't fix your issue.

After the chemtool, I'd star using marvel mystery oil in your tank. I use it in my stang and I can promise you. That stuff is amazing. Best of luck bro.

Usually this is caused by cam timing being off a tooth or so. Now, with that being said, mhs wrote a lot about how far off the factory stamped cam gears are. Not enough to cause that variation, but the widebands could be either going bad or need calibrated. Do the plugs look the same bank to bank, as far as color? If so, don't worry about it. I've never see anyone install dual widebands in a car for tuning. How are you reading these sensors.

NXcoupe said:

Usually this is caused by cam timing being off a tooth or so. Now, with that being said, mhs wrote a lot about how far off the factory stamped cam gears are. Not enough to cause that variation, but the widebands could be either going bad or need calibrated. Do the plugs look the same bank to bank, as far as color? If so, don't worry about it. I've never see anyone install dual widebands in a car for tuning. How are you reading these sensors.

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Isn't the 4.6 very sensitive to cam positioning? I remember from the information video from Ford about the engine. They say if the cam isn't lined up perfectly on installation, then the intake and exhaust valves will hit the Piston.

NerdKrusher said:

Isn't the 4.6 very sensitive to cam positioning? I remember from the information video from Ford about the engine. They say if the cam isn't lined up perfectly on installation, then the intake and exhaust valves will hit the Piston.

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No. I've seen as much as 2 teeth off and no valve to piston contact.