missfire under 2500 rpm

[janvella]

Hello everyone, i searched the forums in hopes of finding an answer to my problem but with no luck , so im gonna ask here .

Basically i have owned my FTO for more than 5 years , its a 2.0l mivec tiptronic .

so last friday i was driving around and i pressed the throttle all the way down and mivec kicked in normally as it should, but then after a couple of other hard pulls, mivec kicked in and the engine started studdering, like hesitating to go past 6k rpm with no power gains at all. THEN it started to missfire under 2500 RPM when idling and on drive,when i go over 2500 it drives fine and mivec works properly too.

i replaced the rear bank spark plugs as well as the front ones, tested the coils and all of them are sparking properly , cleaned the throttle body and the stepper motor as well .
Problem still here , can anyone help me out on this one. would be greatly appreciated .

Thanks in advance .

[brccrx]

When did you last change oil? One of solenoid probably seized due to lack of oil change?

[janvella]

been a while , what solendoid are you refering to , pls

[brccrx]

Yeah, i bought car that had same problem, mivec solenoid i mean, sorry.

[janvella]

car still has the same problem, we replaced the stepper motor and idling went down well, car still hesitates under 2500-3000 rpm , could it be the timing skipped a tooth and its retarded on idle ?, im running out of ideas what the problem is

[brccrx]

Have you lift the rocker covers to check the mivec solenoids, no? Why?