the other day while driving home my rpm's were jumping from about 3000rpn to 1000rpm and back very quick than all of a sudden it quit and wouldent start again i got pulled home and when i got home it started right up but the rpm's wernt right either it would idle high and die or the rpm would jump around and die at first i thought it was my tps but it isnt i just put a new one on today so now im stuck if anybody has any ideas it would help alot

 

could be the crankshaft position sensor. does the check engine light come on?

 

my z did that once and it happened to be a miss fire in the 3rd cylinder so i put high quality plugs in hasn't done it since.