92 300zx n/a
 

OK all you z brains out there, I have a service manual, I trouble shoot electronics for a living. I've checked everything according to the trouble shooting flow chart guides for voltages and resistance, no problems with any sensors or other devices or connectors. I took it to a dealer and had them put it on an Nissan Consult, they didn't find anything wrong, this is the problem.
When sitting @ a stop sign in Drive, idle is normal,when accelerating there are no problems, great accelaration, when coasting(decelerating) RPMs are unstable, when cruising down the highway with cruise on are not, engine misses and coasting from a high speed RPMs are unstable and I would assume if it wasn't for the enertia of the torque converter keeping the motor turing it would probably die.Sitting parked engine idles smooth but standing at the back you can hear an occasional miss.

My first thoughts would be:

vacuum leak
Have you checked your timing?
Speed sensor. Is your speedo working o.k.
Have you checked for codes on the A/T ecu?
Stock or POP air filter? Air turbulence issues.

There is no possible way a bad speed sensor can do what he's describing. The only thing even closely pertaining to the engine that the speed sensor affects is the auxilary fan. (just figured I'd let you know)

Here's the link for hesitation.
http://twinturbo.net/ttnetfaq/FAQpages/hesitate2.html

Check the resistance on your injectors. Should be 10-14 ohms. INjectors could cause your miss, but I'm not sure about the other issues.

he PMd me a told me that it ended up being turbulence in airflow. He did the tape on the filter trick and it cured his issues.