Lancer flat spotting forward and no flat spots in reverse ??
 

My neighbour has a 1996 Lancer sedan 4 cylinder 1.5 lt aoto with carby and mechanical fuel pump.
His car started to bog down , hesitate , flat spot on full throttle off the mark.
Mechanics in sydney changed the leads, plugs , fuel filter and its still doing the same thing. 2nd mechanic shop changed air cleaner, put another set of leads ..... they said the lead the 1st mechanic put on were faulty . who knows, any way I had a look at it and this is what i done so far : put some nulon petrol / injector carby clean in fuel tank and gave the carby a few sprays for carby clean, also checked the auto choke and fuel pump and they are ok >
The lancer still bogs down / hesitates of the mark under full throttle most of the time , some times it doesnt and takes off like a little rocket and give the wheels a spin, but most off the time 90 per cent , it flat spots for a bit and then after 3 or 5 sec , gets going .
Now here is the STRANGE BITS ...... it starts 1st go, hot or cold, it revs without any flat spots in park or neutral and perfect in reverse. yes revs in park, neutral and takes off like a rocket in reverse , but going forward from a stand still its hesitates , coughs and bogs done for a few seconds. Does anyone have an idea on what it could be ? please