Engine light turned on, while I was on the interstate. Pulled over to check, radiator fluid was empty. I topped it off, the light turned off and I was on the road. About an hour passes and it's back on, for every 45 minutes it's on and off. Going about 73/74 mph. When I'm going under 50 it's off.

 

Coolant leak? That water had to go somewhere... Pull your codes to get an idea of what could be going on. Even though your light turned off, the PCM will have stored one or more codes.

 

That's my guess, my temp gauge inside doesn't move either way. How do I tell if there's a leak?

 

Typically you have a pool or a few drips under the motor. You may have a head or intake gasket leak which would drain your coolant into your oil. Check the oil for being milky.

If your coolant gets about 1/2 gallon low, it won't make contact with the coolant temp sensor, which at that point will read whatever ambient temp it wants to.

 

The oil is fine, and after the trip back I've noticed that the engine light turns off under 70 mph. There's no pool or dripping either.

 

Pull the code(s).

 

The only thing that the diagnostic said was the 02 sensor was lean bank. Not sure what that means.

 

Sorry for the delay, but it's planting season. I would fill up your coolant and do a pressure test to see where your coolant is going. A lean code can be a number of things, but I usually try swapping the O2 sensor first. Have you checked your fuel pressure? Replaced the fuel and air filters lately? Bad wiring, or a bad harness connection to the O2 sensor could also be the culprit. Sent from my iPad using IB AutoGroup

 

The fuel pressure is good. I know I really need to clean my air filter. I just got headers installed, and the light is off and has stayed off. The coolant hasn't dropped since my trip, and the oil is still good. I put some injector cleaner in the fuel, it's called sea foam I think. It seemed to help out a bit.

 

Good to hear. I still hate the concept of seafoam, but I can't argue with it when it works for so many people. Cheers