Mi16 Running Poorly Between 3000-5000 Rpm

[B16HBG 0]

Hey guys, i've recently swapped my 1.9 8v engine for the good old 1.9 mi16. I've had countless problems but have overcome most of them now. There is one last issue that i can't work out myself. Driving the car between 3000-5000 rpm it stutters and the revs drop back down slightly. When it reaches about 4500-5000 it takes off rapidly, its just before then it is very unpredictable. i have replaced the ignition amplifier, Crank sensor, Distributor cap and rotor arm, spark plugs. One thing that is playing on my mind that could be the problem, i didn't get a oil filler cap for my engine when i purchased it so i used the one from the 8v and it has two breather pipes coming from it. one goes to the flexi pipe just before the throttle body. the other i can't seem to find a place for so have left it off. Could this be regarded as an air leak and could be the cause of problem? or am i barking up the wrong tree? sorry for the essay but some help would be very much appreciated. thanks henry

[luggy 13]

Do a search on AFM's

[B16HBG 0]

All sorted! The problem turned out to be a spade connector on one of the injector plugs. It was making a bad conncection