engine choking-searched

today i pick this girl up for school, and she lives on a busy road. the speed limit is 50. i pull out of her driveway which is on a hill and i go down the hill. i see in my rear view mirror, a bus, whihc is alredy doin like 55-60. so i shift to 2nd and start getin it, so i dont get mashed by this bus, well the tach hits 5000 and the car starts to choke and sputter, so i shift into 3rd. it hits 5000 again, and the same thing happens. let me add that it was like 40 degrees this morning, but my car had alredy been driving for prolly 10 minutes, so i dont think being cold is the issue. i then approach an intersection. i pull out of the intersection and see if the problem happens again. this time, only, it dosnt choke and sputter, but the tach, once past 5000, starts to not just climb gradually, but jump up. I could not figure out why it sputterd liek it did. but the tach jumping also has me thinking. so then today after school, i go to leave and get in my car and it dosnt start. i sit for like 30 min then it finally starts, but when i hit the gas, it just dies. it starts agian, i hit the gas, it starts to die, i let go, it comes back, i hit it agian, and it dies agian. it wouldnt start anymore. then, naturally, right when my dad and brother come up to my school to pick me up and see if they can figure out whats wrong with it, it starts right up and the gas works regular. the tach thoough, is still jumping once past 5000. i am completly in the dark on this one. my friend says it might be a valve problem, but i dont no. and also, the other day, i was drivng my car, and i went to shift to third and it ground a little going in, but i figured it was just the synchro becasue its going bad in 3rd gear, so i shifted, and let the clutch out, and the entire car tries to come to a screaching halt, the tach is going crazy, boucning from 1000 to redline, and the tranny is grinding like a mother. i quickly presed the clutch back in, and pulled the stick back to neutral, then put it back to third and it went fine. now, il admit im not the greatest driver, or even close to it, but i dont think that was my fault. can anyone tell me whats goin on with my car, cuz its starting to bother me. and now i just got it back from the shop to see if a mechanic could fix it but he did not even notice a problem, yet when i got back in the car, it is still doing the same thing. when t gets past 5000, it pops, jumps, and sends the tach flying. wtf is wrong. :wtf: