mrprofile

so this is a weird engine problem, I have a 1979 280zx N/A, all stock engine components where it counts, it will run fine day in and day out, but if I warm it up, then shut it down and leave it for about 15 mins, maybe 30 mins, and go to start it, it idles very roughly at about 300 or 400 rpm and when I step on the gas it will power through the roughness, almost as if its misfiring as its doing so, and under the hood I hear this mysterious random pop, like slapping your hand on a table when i rev the engine, after about a minute it is completely gone, and the engine runs fine. does anybody know of any kind of device that is on for the first few minutes of the engine running, but shut off soon after? im thinking a heat sensor or something could be malfunctioning, and be telling the engine its cold so it should activate the cold start valve, and give it more fuel but I dont know if the car would be that advanced. any ideas?

NismoPick

Sounds like your AFM needs some adjustment...

Also, check for vacuum leaks, timing, and all sensor connections.

The CHTS is the "heat sensor" you speak of. You can do tests on it too... I've posted the tests here before.

mrprofile

alright, thanks

mrprofile

I think I solved it while looking for vacuum leaks, for anybody in the future who has this problem, a tube was not connected to the top of my "fast idle actuator" which is on ZC-21 in the 79 fsm. it makes perfect sense