Code 37 has to do with Torque converter clutch solenoid CKT or park/neutral switch failure IIRC...one time my downstream o2 sensor came unhooked because someone
broke the clip, and it set a code for too lean.

 

So how would I go about fixing a 37. I only have 1 o2 and I tested it. Seemed fine. Think I'll swap it out to make sure its reading 100% since its cemented in mud.. Haha

 

Reset it, and see if it comes back.

 

Just to let you know, our trucks are fuel injected so they don`t have a carburetor, they have a throttle body. There is a big difference between the two.


If the inside of your plenum is covered in oil the plenum gasket is toast and needs to be replaced as soon as possible. That would cause the bad gas mileage your getting.