fluctuating idle, lack of power, new rev limit at 5k whats happening???

[ange]

Hi (new here not sure if in rite section apologies if not)

Any way my problems started a few months back so far i have tried changing MAF, Throttle body, new throttle body gasket, knock sensor, IAC sensor, removed EGR to eliminate that, removed the second cat first cat visualy inspected and fine, changed both o2s, compression test came back fine, VICS all ok, Intake manifold gasket changed at same time as checked VICS, changed spark plugs too. fuel pressure fine, checked and cleaned all earths i can find, fuses relays etc. no fault codes. dont no where to look now.

My car is a mazda 323f 2003 2.0 sport, 85,000 miles, cold air feed, and stainless exhaust system no other mods.

cold start up idle is at anywhere between 2000-1000 rpm, once its warm its fluctating between 600- 750 rpm.
car should rev to 6500-7000 rpm but now its hit this problem its done at 5000 and once you get to 4000 rpm it sounds like its just come on VTEC but going nowhere power loss throughtout all the rev range

only way to explain the loss of power is i got out run by a 1.2 corsa.

any suggestions would be highly appreciated because i have no idea what to try next.

thanks

Aaron

 

[concept]

What does vacuum pressure look like at idle?