on a cold start morning or hapon after galing office: bumababa ang menor ko kapag mag headlight/park light and kapag steady apak sa brake lalo na kung trapik..minsan namamatayan talaga.during cold start lng naman.pero kapag mainit na makina mga 1/4-half temp.ok naman..need your inputs mga master....
Hi not really an expert but used to own a Lovelife Corolla, from my experience ganyan din. Every morning and after parking it for a whole day sa office especially when the headlights are on and braking for humps, definitely mamamatay and engine ko nun. I tried everything and nakita ko sa internet na baka IAC daw. Didn't help. Anyways, the culprit in my case was a torn rubber hose coming from the Air Intake metal thing sa liked hung cylinder head(?)(not sure what it's called sorry) going to the back of the engine. Try to ask a mechanic kung may mga tears or something. After this was replaced, my idle was back to normal and fuel consumption improved din. Hope this helps bro!
based on actual experience.
diesel engine using caltex monograde sae40: lumpy low rpm at cold starts
changed to castrol gtx 20w50: significantly smoother and rpm increased at cold idle
conclusion: use lighter oil for better cold startups