here in nz i have an 84 civic 3 door, f1 "AT" chassis civic. It is a jdm formula one factory special with embroided seats special trim etc.
It have an intermittant mis fire that comes and goes at 4,200-4500 rpm.
so far i have changed the fuel pump,filter,pres regulator, checked injectors, new plugs, leads(NGK),tried new Map sensor box and distributor and cap and rotor, new coil, new tps and water temp. different ecu, gutted the cat convertor( not required here) tried different tdc sensor assy. thought i had found it with an engine earth wire problem but still there from time to time ...even done the cam timing!does it with the filter to plenum chamber tube removed so the buteerflies can be seen working
it does not throw up any error codes... it just wont rev cleanly past 4500 rpm YET the next time i drive it, it will!!!
when it will rev cleanly it appears "flat " in the mid range and when it starts to miss it will pull strongly until the misfire sets in.
any ideas appreciated
thanks stu

 

must be someone who has had this fault?

 

sounds like an ignition problem