Hey there, 75 280z here. Stock original engine with fuel injection. Geting really low and rough idle when car first started. It almost doesn’t run until I pull the vacuum hose off the FPR, then it idles much better and warms up quicker. And yesterday I drove it like that with the FPR disconnected and is much faster and smoother. What could be wrong here? I’ve checked all my readings per the ‘fuel injection bible’ and they are all accurate. Also when I unplug the cold start there is no change at early startup. Any tips for items to check would be most helpful thanks.