Hey all ... a few Quick questions

Ok, i drive my MCS everywhere, all day it seems... i have about 11k on the clock. Yesterday, Out of nowhere , the car started to pull to the right. It happens when i break and when i dont... i can be driving down a flat road, take my hand off the wheel and it'll dive right. I haven't hit any bad bumps or curbs or anything.
Has anyone else come across this problem?


Also, i still have like 700 miles to my first service interval, i thought it was due at like 10k. I have changed my own oil a few times, would this effect the service interval?


Thanks for your help...
mike