99 Blazer problems...
 

Not sure where to start with this, so I'll just start. Sorry if this is too long.

A couple of weeks ago, I managed to drive into high water (stupid, I know). It stalled the car, which wasn't a surprise. Once I got it restarted, I didn't have problems until the next day. My RPM's were revved too high, even without my foot on the gas. The gas pedal had felt sticky for awhile, so I cleaned the throttle body, which seemed to solve the problem. Now, that problem is mostly gone, but still kind of returns, I have a more concerning issue.

My RPM's have to go waaaay high (3000 or so) before the gears will shift (it's an automatic transmission), and I have to let off the gas and thread it a little for it to go into gear. I've also noticed that when I go from a stopped position into reverse, the car jerks backward, and it does the same when going into drive. The service engine light has been on since all of this began, but I don't have a code reader to check it.

I'm hoping this isn't my transmission going out, because I haven't had any transmission problems at all leading to this.

If anyone has any thoughts or suggestions, I would really appreciate it. Thanks for your time.

Well it sounds like a transmission issue but that isn't necessarily horrible news, could just be a loose connection. Take your car to an autozone or the like and get the code. I also read a great diagnostic for transmission problems on this forum. Search "transmission problems" and.see what u can find

You might try checking out the links in Kyle's signature it has some helpful information.
https://blazerforum.com/forum/members/swartlkk-577/