royceta59

hello fellow yotatechers, let me start by saying i've spent the last three hours reading every thread about 3vze idle issues, and quite frankly i'm still at square one. my runner idles between 1200 and 1500rpm, runs great cold but as soon as it begins to warm it starts stumbling and missing while continuing to idle high.
i've replaced the cap, rotor, coil, plugs, plug wires, coolant temp sensor and "almost" every vaccum line. plugs have stayed dry (no oil or water) and i have compression within the tollerances. no trouble codes.
i would appreciate any input, i'm loosing my mind battling this nutless pig. thanks to all and appologies for this repeat thread.

and if it makes any difference the previous owner cut the wires to my egr temp sensor. i pinned it and reconnected it a while ago. still same story.

WartHoggRunner

Hi, I am having a similar problem with my 90 3vze, mine starts missing when in higher rpms, or if I put it under too much strain, such as shifting into 3rd when going 20mph. Replaced cap, rotor, tps, wires, coil. If you haven't replaced the tps (throttle position sensor) that may help. I pulled mine off and checked it, it was pretty out of wack. replaced it but it didnt fix my problem. Put new coil in yesterday, didnt fix it. Next thing left is the ignitor I guess.

Codytr1

I got the same problem but no miss.

nv4runner

High idle problems bring too much air or too much fuel to mind. Try disconnecting the cold start injector when it'd normally be idling high.

Prerun4fun13

man my truck does a funny thing to idles fine when cold then idles really low when hot..
free bump

WartHoggRunner

Well I figured out the problem, Bosch spark plug fell apart inside my #6 cylinder (back driver side is 6 i think). The whole center cone was completely gone. Had 25K-ish on them. Feel kind dumb for not checking them all first, but I do things the hard way every time. Like when I dropped my tranny 2 times just to find out it was the clutch pedal bracket, i needed a new clutch anyways.

Cuba

Mine did exactly this when I first got it. Coolant runs through the throttle body and as it heats up, it closes a valve bringing your idle down to normal. Normal cold start cycle. I have a feeling it was this valve in my truck. Cleaning it out helped a little, but I still had irregularities. I changed the throttle body yesterday and although it doesn't drop like that now there seems to be a few tweeks to be done. It doesn't drop way down like it used to though.