I have a 77 280z and Ive noticed that if Im cruising anywhere from 50 to 75mph the car Lags or acts like its trying to stall.

The car never dies, When it does this the Tach and Speedometer dont show any changes at all, but I can feel it. Kinda like if you were to lightly pressing on and off the gas.

Any ideas for me to start looking when it warms up?

A Pic of my beauty:

Sounds like fuel. Have you checked the pressure. could be clogged lines or poor conections to pump. My guess is the lines. but there are way more possibilities.

I guess ill try that out the next warm day I have off it sounds like a pain in the arse to do though.

but thanks for the info

fuel, carb adjustment, filter been changed... low power all the way or up hill or??

Its power loss can be felt going up or down hill and on level surfaces. I dont really think its a carb problem or even a fuel problem really because it runs great at idle and any speed up until 50 mph.

Definitely not a carb problem, unless the EFI has been removed and replaced with carberators -it's a '77, right?

Could be an AFM problem- weak carbon track under the wiper contact at that RPM/vane position- causing a very minor rich/lean condition. I've had this happen.

Check the throttle position switch. Corroded contacts, misadjusted...

Edited February 26, 201213 yr by Willoughby Z
another thought...

I dont have carbs on there. I thought it could be an electrical problem maybe loose injector wires? idk

I dont know where any of the things you just mentioned are, I do know where the AFM is haha but not any contacts or terminals associated with it. Any help?

EFI "bible": http://www.4moores.com/280z/files/280zfuelinjectionbook.pdf

Factory Service Manual (FSM): http://www.xenons30.com/reference.html