Nissan Repair: 82 280ZX Turbo misses?, vacuum leak, drivability problems

Question
Stock 82 280zx turbo has developed intermittent miss. Cuts out about 2500 rpm in first gear, pulls hard through full rpm range in second but valve knock at about 4000rpm, in third gear it pulls hard until about 3200 rpm it begins to cut out. If I back out of the throttle in 3 gear it will go ahead and run the rpms up but it lacks "balls" that I have become used too. Idle is unstable and the misses/drivability problems are considerably more pronounced when the car is cold. Thought maybe cap, rotor, plugs, wires would solve the problem, but it hasnt solved problem. Was thinking that I have a vacuum leak, but cant find one; or maybe the timing chain has stretched allowing for greater variables as the ecu tries to adjust timing for boost, load, or rpms. Making me crazy so any help would be greatly appreciated. Thanks in advance!


Answer
Dghale,

First, the distributor is probably contaminated with oil and needs to be replaced.  Second, the waste gate is probably opening too soon and that is why the car is falling on it's face.  The chain could be stretched.  But, that is probably not the cause of the problem you describe.  I would first check the two things I mentioned.