like when i start it up it runs fine for about a minute or soo...then when i shift and i press the clutch the rpm's may go up about 1500 rpms ,..but i had a idle isue a while back where it would idle high soo i attached a sping on to the hood lock thing and the other end to the accelerator bar thing,...well it is better ,...but the only way to make it not do that is before i shift i let off the gas,for a while then i shift and the rpms fall like allways like normal ,... oh and its a 78 280z 4 speed fuel injected,..i was thinkin it way be the clutch or some thing with a vacum hose,...and i was wondering what would be the best clutch for an L28 for raceing,..and if theres any low prices for cowl induction hoods,..i found one on motorsportauto but its 599.00,.... hell naw!!! and some differential ,..or driveshaft upgardes,.well thank you guys

could be the BCCD, have you checked that?

Okay, I wish I could help you more but there is a component that is attached to the throttle assembly that is designed to regulate your idle in the middle of a shift. I'll figure out what it is.

Before you go and spend $600 on a racing clutch, you should take care of your ECU sensors first.

Do you have a factory service manual? You can download it online from www.carfiche.com (at least the '76 and '77)

You might also want to examine the idle bypass screw.

Okay, I wish I could help you more but there is a component that is attached to the throttle assembly that is designed to regulate your idle in the middle of a shift. I'll figure out what it is.

Throttle position sensor? A bad one or badly adjusted one could casue that problem. Also the altitude switch but only if it was originally a California car. There are other items to check also. An FSM would be your best bet since it has a troublshooting algorhythm for EFI problems. Racing clutches and cowl induction hoods etc. won't do much good if you are unfamiliar with the EFI system.

Throttle position sensor?

Yup, that's what I was thinking of... I think...

I thought there was also a mechanical/vacuum operated component that controls how quickly the throttle closes when you let off the gas...?

Dashpot.