To my knowledge pretty new. I know the front one is NTK and it is switching.

 

You only have one front O2?

 

No I have two but the rear was not switching that much around .20 instead of almost a volt. I may just replace the map sensor and both O2. I think I may have a front driver's brake locking up. When I turn it around like it's burning tire.

 

The short term fuel trim at 25% is way too high. It would explain the rear O2 being maxed out at 1V and the bad MPG. At the same time the front O2 readings look right which doesn't make sense given that the readings after the cat are much higher. I wouldn't trust the front O2 sensor readings, might be a bad part or Amazon/ebay counterfeit. How does it behave with the front O2 disconnected ?

 

Didn't tty that, but it is a genuine NTK. I'm just going to replace them both and the MAP sensor

 

If your calipers are old and rusty, you might have one binding. However, you might also have a hose collapsing inside on the flex hose to the caliper. Drive a bit and then jack the truck up on the hot wheel. Take the wheel off and open the bleeder valve on the caliper. If you can't rotate the rotor by hand then you release pressure and you can, you have a failing flex hose. If it doesn't make any difference, your caliper is binding

If you replace a hose, change both front and your rear hoses. They seem to last forever but they can lock a wheel up or blow out and you lose brakes.

 

Just FYI, I purchase my flexible brake lines from these folks - a bit more expensive, but I buy once and I'm done - https://www.crownperformance.com/

 

I am going to do that once I get time to look at it again. The plan is to use my laser thermometer and see if any of the wheels are hotter then the rest.

 

I use sstubes. They offer stainless steel brake line kits and I use their kevlar braided soft lines. They look pretty 😂😂

 

Did you use the 2003 ram lines?