Got my 79' 280z back from the shop recently for a diagnosis. It died on me after a bit of spirited driving one afternoon. I thought it might have been an issue with the cruise control because I had flicked it on and off a few times to see if it still worked. Turns out it was actually a bad MAF sensor. Got a new one put in just yesterday and now its running really rich. Low throttle response until you get it warmed up, backfires when you let off at high RPMs, and I can hear a hissing sound coming from the engine bay when running. My guess is a bad vacuum but I figured I should see what yall have to say about it. Anyone else have this issue before?