I have a buddy with a 2000 1/2 ton Ram 2x4 with the 5.2 and automatic. He is helping me with some drywalling, and mentioned that his truck is only getting about 11 MPG. I told him that I thought that was quite low for his setup and started asking questions about the maintenance.

Anyway, long story short, I am going to be replacing the spark plugs and air filter for him in the next couple of days while he finishes up the drywalling. The truck has 140k on it and he hasn't changed the plugs or filter, but it is used and I don't know about the original owner. I'm guessing they might be original. The exhaust has a very strange smell, like unburned fuel, but also something else that I can't figure out. Thought maybe cat converter is plugged? No CEL, but I haven't tried to check for codes either. Does the 3 cycle key trick work on a 2000?

He also told me that he uses a little oil and loses a little coolant. The oil looks clean and is leaking around the valve covers, so I don't think it is using any, but can't really tell for sure. Anything else that I can check for him? We had a Durango that got more around 15-16mpg with that engine, I would think he should be close? Thanks for any help.