Hello again.

Confession time:

Guys, I'm really worried. I just now checked the oil. It looked bad, very black and dirty looking, it looked burnt. The thing is, I just changed it on Saturday. I've been changing my oil every 3000 miles because I'm doing 500 miles a week, but I went 500 over because it rained all last week and I just didn't feel like it. Well, when I did change the oil I was almost a quart low, never happened before, and it must have gone in the last 600 miles because the last time I filled up I didn't check the oil, so in 6 days I lost a lot of oil.
I wasn't super worried, because it was 15 degrees when I checked the oil and I hadn't run the car all night, figured it was cold. Now I'm worried. I've been using Castrol Syntec blend, and Purolator filters and up till now when I checked or changed the oil it's looked really good almost a waste to change it. This time it looked really black in the pan, and today it looks really dark on the dipstick. I'm using a Bosch filter this time, it was either that or Fram, the stock is never the same at my local autozone, and it felt kind of light.

I've been having problems with my temp gauge going up and down when I drive, so I don't know if I've been running hot or cold, I haven't noticed any smoke out the back or oil in the engine compartment. What can I check? Any ideas? It's been 104 miles since I changed the oil.

Thanks greatly in advance

Terry