Yaris T Sport problem,bogs down after 4000 rpm

[allant]

My Yaris which i have had for 6 years has an annoying problem,it all started after i changed the clutch,it had a small hiccup when changing up the gears, then started to gently miss at high speed.

Finally after months the engine light came on, the car started to bog down when revving past 4000 rpm & got even more jerkier on the upchanges.

I took the car to a garage who had a Snap on scanner with latest software,it came up with weak on Bank 1, so a new Denso 02 sensor was fitted before the CAT.

On the live running the figures were better than before but the problem is still there.I have cleaned the MAF sensor, taken the OCV out & put 12v across it & that works fine, i did check for voltage

on the plug, but there was nothing on tickover, so i am assuming it would become live at 4 or 5000 rpm to alter the cam timing,i have changed all the spark plugs, checked resistance across the coil

packs,all seem ok.The wires to all the sensors look in good condition, the car has done 73000 miles.

Anybody out there know what else i can try to solve this issue.

[AL21784]

Have you looked at the crank position sensor?

 

Alan

[allant]

No i have not checked that out yet, is that a possibility that it is faulty, would it have come up with a code, i thought that would either work or fail completely, but i will check it out,thank you.