GPA issues

Do I even stand a chance at Stanford if I have a GPA between 3.85-3.87 by the time I apply to colleges?
Freshman Year: 3.88 GPA
Soph: 3.80 GPA (ouch)
Junior Year: Expected - 3.93-3.95 GPA
–> Senior Year: 4.0 Ideally (not counted for cumulative)
Should I aim for a higher standardized testing scores to make up for this less than stellar GPA? I have decent scores in subject tests, and am taking the ACT this year. It scares me to see that literally all the posters on the Stanford Results Threads from past years have GPAs >3.9.
My school doesn’t rank and the cumulative GPA is the average of only freshman through junior years. If I do well senior year would that make up for this GPA? The cumulative GPA that shows up on my transcript is displayed separately from my individual senior year first trimester one (but aren’t most high schools’ cumulatives a 4 year average?).
My school is known for sending a decent # of students to top schools-- the senior class (above me; I’m currently a junior) has at least 4 acceptances to Princeton and varying #s for other schools, etc. Also, a decent number of students in my grade have 3.9+s, which scares me but like I said, my school doesn’t rank, so how much would this hurt me assuming I have decent extracurriculars?
Also some more information about my school: for my school, a 95 and above for the sciences & foreign languages is considered a “4.0”, a 96 and above for history/social studies and a 97 and above for math. English is a little more arbitrary. Otherwise, 90+ to these cut offs is a “3.8.” My school also does not offer any APs. From what I’ve heard, most other high schools consider anything above a 93 a “4.0” equivalent. This kind of disturbs me cuz I’ve had a 96 average in math sophomore year but it counted as a 3.8, and only the letter grade is displayed on the transcript sent to colleges. Also, other friends of mine easily get 4.0s with little effort (even in AP classes!). So again, what I’m asking is: do I stand a chance at such top colleges as my school restricts me to applying to a limited # of schools, and I don’t really have an upward trend-- it’s looking more like an up, down, then up (ideally!) trend.
Please let me know what you think!

General consensus is that if you pass a certain threshold academically you will have a shot and the rest will be up to other application components. A 3.85 UW is within a reasonable range to be considered for admission. So yes you have a chance.

With that said, keep in mind 95% of students admitted to Stanford were in the top 10% of their classes. Your school might not rank, but you mention a decent number are 3.9+.

Outstanding ECs and good test scores will help. Don’t fixate on the"top colleges." Be sure to apply to a range of safety and match schools. Good luck!