Quick Jerk When Letting Off Of The Excelerator Pedal

[280ZJP]

Car runs great, except for one little quirk.  While driving at highway speeds, 60-70mph, if I let off the excelerator there is a quick jerk that scares the heck out of the passenger.  (I know I'm letting my foot off the gas, but the passenger doesn't)  I was told the problem may be in the drive train so had that all gone thru - twice - and still no dice.  Problem still exists.  Also checked the vaccum advance and it made no difference.  Anyone else having this type of problem? 

 

[Zed Head]

Jerk forward or backward?  What RPM?  Stock 280Z EFI, all parts intact?  Could be fuel cut at 2800 RPM.

[280ZJP]

jerk backward.  about 2000 rpm?, stock EFI, all parts intact. 

[siteunseen]

Dash pot rod may need adjustments. The white plastic thing with an open hole that looks like there is hose missing.

Or maybe the BCDD?

[rcb280z]

Is the drive train original?

 

Standard or auto?

 

Gone thru twice meaning what exactly? 

[280ZJP]

The differrential has been take out and checked to match correct specifications.  Standard transmission.  Tell be about the BCDD.

[siteunseen]

Here's when I was fooling with mine, http://www.classiczcars.com/topic/42497-bcdd-removal/

 

You could pull the wire off the solenoid to disable it and see if has any effect.  

[Chickenman]

jerk backward.  about 2000 rpm?, stock EFI, all parts intact. 

2,000 RPM sounds too low for 60 or 70 MPH. Double check that RPM. If it's anywhere near 2,800 RPM ( + or - 200 RPM ) it could be just the Fuel cut...which is perfectly normal. How bad is the jerk? Unless it's really big, best solution may be to find another passenger who's less " nervous "...

 

Seriously, could also be the BCDD as previously mentioned.