power dips after 5000rpm? please please help

Hi all

After figuring out my Super S had a injector stuck open, which made my micra run on 3 cylinders and over fueling the 1 cylinder, i changed one, then all the injectors with a set from a cg10de 1.0 1997 micra.

When I replaced the one injector it was quite an improvement..... ran on 4 cylinders again! but the power has a big dip of lower power at 4500rpm - 5000rpm, while accelerating at that range. It dips and surges but mainly dips really bad, accelerating doesnt help it feels as thought it fuel starving.. but i am not sure. But revving the engine under no load it revs climb freely towards 6000rpm with no problems.

I then thought to change all the injectors with the 1.0 micra ones i bought and its the same, but the range where it dips is around 5000rpm to 5500rpm now. I cant put my foot down like i used to and the car springs to action, it bogs down but if i very lightly accelerate it gradually picks up speed after that range but slowly and still bogs down

Any ideas on how to fix this tiny problem, any testing methods to figure out whats going on?

I have just checked the timing (@15 degrees, but scantool says its at 20 degrees when idling is that ok?), TPS is set at 0.48V

I have a data cable and when the car is stationary the fuel mixture is rich. the micra has a 1.4 almera airbox, a plr exhaust, a brand new TB from Taiwan, tried 2 2nd had dizzys, new spark plugs, leads, air filter, timing set at 15 degrees, O2 sensor isnt even a year old, oil and oil filter changes a month ago..

Hope any of you all can help, a micra super s that cant keep up with a 1.0 yaris until it gains speed using the gently accelerate method is so disappointing :(

Please help

its probably just a lean patch in the fueling, made worse by the mods, have you disconnected the speed sensor input ?
and you have to sync the strobe timing with the datalead timing, so that both are set to 15deg

Speed sensor unit? the connection on the back of the speedo? or the cable that goes into the gearbox? removing that does what exactly, sorry to be so useless

Ahh so use the datalead and the strobe light until both measure 15 degrees?

Thank for the help

yes 1 if the screws at the back of the speedo mate (that connect to the circuit board) and that stops the ecu closed looping when it gets to a set mph threshold
and i always set the strobe timing to whatever the ecu is holding it at personally, so if the ecu is running (for instance) 20 deg, the dizzy is synced at the same 20 deg