'78 280Z Running Rough: Video

[OldSkoolFool]

Hi Z enthusiasts.  I have a '78 280Z with 64k miles and is in stock condition.  I have never had the problem I am having right now with it in the three or so years I've had it.  It has just started to run somewhat rough, almost like it is not running on all cylinders, maybe down one.  It holds an idle but is not as smooth as it used to be.  When driving, it feels down on power throughout the rev range and no matter how much throttle is applied.  At idle, it will gradually accelerate overall fine but still with somewhat of a stumble, and as mentioned down on power when driving.  When more abrupt throttle is applied, the engine stalls for a second or so before it revs up.  Below is a video of that symptom.  I am looking for advice on where to start.  The fuel tank has been restored when I first got it about three years ago.  A couple fuel system items have been replaced (ex:  filter, pressure regulator?, one injector, etc.).  It seemed like clogged injectors were a common problem on these cars.  Those can be checked with a stethoscope?  I checked to make sure the plug wires were tight.  It is bad enough to warrant not driving the Z.

 

Thoughts?

 

Regards,
Shane

 

 

 

[Dave WM]

check for Air leaks, check plugs see if any look more fouled than the rest. The video was so short seemed like the issue was just a slight hesitation.

check the temp sensor to the EFI. Don't start messing with the AFM spring tension, go for the easy stuff.

[Zed Head]

Clogged air filter?  When you open the throttle like that all that you're doing is allowing the engine to pull in more air.  There's no accelerator pump like a carb'ed car.  The fact that the engine doesn't "grab" more air could be because it can't or something's out of time.

Has it had a good tuneup in the last three years?