NissanForums.com :: Nissan Forum - View Single Post - 1990 d21 HB rough idle after warm- yes i searched

scout · Oct 24th, 2007, 10:36 AM

So in summary, the truck does fine idling until the engine is warm and then it starts to rough idle. Which is a pain because if you do not yo yo the throtle it will shut off in traffic, then very hard to restart.

I don't know anything about the 90 specifically but it sounds like the extra fuel needed during a cold start is not being terminated after operating temp is reached. By yo-yoing the the throttle you are increasing the engine speed and it is able to absorb the extra fuel with the higher rpm.
Hope that is of some help.

Oct 24th, 2007, 10:36 AM	#2 (permalink)
scout Nissan Enthusiast Join Date: Aug 2007 Location: greensboro, nc Posts: 57	So in summary, the truck does fine idling until the engine is warm and then it starts to rough idle. Which is a pain because if you do not yo yo the throtle it will shut off in traffic, then very hard to restart. I don't know anything about the 90 specifically but it sounds like the extra fuel needed during a cold start is not being terminated after operating temp is reached. By yo-yoing the the throttle you are increasing the engine speed and it is able to absorb the extra fuel with the higher rpm. Hope that is of some help.