I hav a 1986 Nissan 720 Pickup, Z24 motor, carburated, 4wd, 5 speed. I have been having this problem for quite some time but I can correct it by just reving the engine and letting it drop back to idle. It only happens after the enging is warmed up. While driving, if I take it out of gear to break it will drop to idle then idle will raise a bit then it start loping. If I rev the engine a couple times then let it drop to idle again it will idle fine with out a hitch. If im downshifting while stopping and engine breaking it will start loping maby 50% of the time while just taking it out of gear and not engine breaking it happens maybe 70% of the time. I dont have any loss of power or hesitation while accelerating or any other type of performance loss. It will also start loping if I just start up the truck and let the choke kick in and let it warm up just sitting in the driveway, after it gets to operating temp and the choke kicks off is when it stars to lope. I rev it once and it idles fine, but this truck has done that sence I can remember when my dad drove it. So I dont know what it could be. The carb freshly rebuilt maybe 1000 miles ago so I dont think its that. Just put a brand new air filter so I know is getting plenty of air. The only thing I can think of would be the EGR valve possibly or something in the inner workings of the enging witch im dreading sence this it my daily driver. Please help. Thank you.
Friday, February 3rd, 2012 AT 3:29 AM