Nissan Repair: 86 HB 4x4 misses @ high rpms, nissan 4x4, air screw

Question
QUESTION:

Joined: Jul 2007
Posts: 1
Car:
Rep: 100 86 HB 4x4 misses @ high rpms

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hello, my name is Joe and im from NC. i just purchased 1986 nissan 4x4 king cab with 94,000K its a 5spd. its the carborated/injection inline4 with 8 sparkplugs and it says elecrto injection on the air cleaner. if you drive the truck like a grandma through 1-5000 rmp it runs great, but when you floor it it goes smoothly up to 2,000rpm then sputters really bad until about 3,500 rpm the smooths back out. also the tach. is all over the place? i dont know what to do. i really could use the help, thanks alot regaurds Joe. i also tried adjusting the idle and turned the little skrew on the side of the carb next to that sensor, then i realizied that it was not the idle skrew. and i found the right screw and fixed the idle but the truck still has a miss at higher RPMS and it jerks sorta when it misses




ANSWER: Joe,

I would think the problem is with the distributor breaking down since it has an optical trigger and with year of the vehicle that is a common problem.  Now, you have done a tuneup replacing the plugs, cap, rotor and wires.  If not do that first.  But, my experience says distributor needs to be replaced.

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QUESTION: so that screw had nothing to do with it? and what about the tach going crazy? but the truck seems not to miss when its cold. i will go take the cap off and check all components, thanks

Answer
Joe,

The screw you describe is either the idle adjustment screw that is set to where the throttle plate just closes or it is the minimum air screw used to set air the engine gets at idle.  Miss under load at temperature usually relates to bad plugs, coil break down or a oil contaminated distributor.