5VZE Rough engine on start only

[deadcandance]

Hi guys I need help. 1999 4runner, 197k miles. New plugs, new wires, cleaned throttle body, no CEL illuminated. When I initially start the engine cold or even warm, it will momentarily run slightly rough and perhaps "misfire" for about 5 seconds and then goes away and smooths out. Runs perfect otherwise. When I go back to start it up it after it's warm, still seems to always stumble a little on start and run slightly rough and then smooth out. It doesn't lope or quit, just runs a but rough for a few seconds. The engine otherwise produces excellent power and runs and idles perfect. Does not ever produce a CEL.

Ignition coils? Start ignition system problem? (if there is such a thing?) Fuel injectors??

I've owned another 3rd gen 4runner and it didn't do this.

Any input greatly appreciated.

 

[THatfield]

Try cleaning your throttle body and Idle Air Control (IAC) valve (it's on the bottom of the throttle body). I'm about the tear mine apart to clean both of those, as I am experiencing an irregular, rough idle when I start up amongst other things. Cleaning both with Carb Cleaner is the norm. Here's a video i'm going to use along with my FSM to help me do the job. Keep me updated on what happens, and I'll do the same. Good luck!

https://www.youtube.com/watch?v=RgpIg-WkwOY