Hello im new around here and need some help. i have a 300zx z31 na. that is surging strangely at idle and any cruising speed but not under deceleration or acceleration. the car kind of pulls then dies out repeatedly over and over. similar to if you were to take off in to high of a gear or slow down with out downshifting. it is throwing a check engine 21 and 41 ignition signal, power transistor crank angle sensor fuel temp sensor air temp sensor are all listed under these codes im hoping some one out there has had very similar exp and can hit the nail on the head before i start ripping my parts car to pieces trying random parts. it has also recently started doing it during acceleration in first when the engine is not up to temp on cool days