The300zxDude

so my car (93 300zx 2+2 manual, stock) usually idles around 1k maybe a tiny bit over. i tried to adjust my idle from stuff i read from a forum i found the other day and once i plugged the iacv back in it went back to 1k. i was ok with that. well i was driving the next day and when i went to take off from a stop sign it hesitated really bad and almost died. 5 minutes later i was at a red light and it stalled. tried to start it and it just kept cranking and wouldnt start. so i stopped for a few minutes and tried again and after a few seconds cranking, it started and drove fine. well today while driving my idle started to climb to 1500 rpms and stayed there for a little then went back to 1k. next thing i know, they climb to 2k-2300 and i started seeing white clouds from my exhaust in my rear view mirrow. got to a red light and it hesitated again almost died and i decided to take it back home. i got maybe 10 blocks from my house while all this happened. i dont know whats going on. ive also noticed my oil pressure gauge has been low around 10 while im driving and randomly goes to 50ish then to 10 for the remainder of my drive. ive read alot about them being bad so ive been hoping mine is just acting up. my clutch is also slipping so im not sure if thats why it almost died at stops while in first gear. i also just got this car 2 weeks ago and with the clutch slipping, i have the remainder of my money going towards the clutch all the seals and other things im going to replace while the trans is off. side question, is 400$ reasonable for labor on a clutch and other seals? also this car has sat alot within the last couple years, drove a few times in the summer and then back to its parking spot. i could really use some advice, im new to the 300zx but know a decent amount on cars.