-03 Vvti D4, Cold Engine Problem

[CheapThrills]

Hi!

First of all, I beg Your pardon, there has to be a thread about this already but I could not find a proper answer through search...

(feel free to just link)

Problem is, some stuttering or un-smooth driving when engine cold.

Avensis 2.0L petrol, VVTi D4, year 2003 and 110´000 miles on clock.

All services done By The Book.

Always driven on the 98oct.

Got the car 3 weeks ago, had some stuttering when driving with cold engine ->

Replaced the plugs with NGK K16R-U11 Iridium but to my surprice, it went worse.

Oil, filter, airfilter, all Toyota brand and new.

Had a fault code before these: Lambda sensor; bank 2 sensor 2.

-> replaced with original Toyota part. No CE light, fault code gone also.

When started (now on summer), starts good, revs up to 2K RPM, rapidly decreases to ~1500RPM, runs idle well.

Revs well. When driving and pressing clutch, idle speed @1000-1100.

When driven, for the first mile gives some stuttering. Mostly when you press accelerator smoothly and increasing (or trying) speed steadily.

After that, cannot figure anything wrong. I mean, when it gets some heat.

I have HEARD of solutions like:

- Updating some software of ECU

- Changing MAF (how to check if necessary?)

- Changing some "pressure valve", still a bit mystery to me.

Ehm.... So, should I do something or just Deal With It?

Any estimate for the severity of bankruptcy?

Thanks, best regards:

- - CheapThrills

[CheapThrills]

Something to add:

I contacted the local official Toyota repair shop.

Their only good guess was to do a Forte -treatment to clean possibly dirty injectors.

I have already done one treatment recently and it did not help.

Still no fault codes.

Going to take the car in and let them test drive it when cold and plug in some engine data reader or such to see what could be wrong.

Otherwise, there was no ideas of what could be wrong.

[CheapThrills]

All seems to be in order, no codes, values when driven OK.

"It should be like that", stuttering when cold.

I rest my case, no more digging for the fault if it works otherwise! :)