[Gray88]

I need your advice! I have an 88 Toyota Pickup, 22RE, M/T. The idle is too high when I come to a stop. Sometimes a blip of the throttle will bring it down a bit, but not enough. The throttle cable works smoothly, and the throttle valve itself moves well and is not sloppy. If I rotate the throttle valve counterclockwise when idling (to fully closed position) it brings the idle down to normal (it only moves about one milimeter).

At first I thought it might be the Dashpot (DP) diaphram, but when I push the plunger down (away from the throttle valve stop) the idle stays too high. Could it be the Auxilary Air Valve Assembly (P/N 22230-35010)? It is an expensive part, so I want to have a good idea it is the problem before replacing.

 

[HEAVY_GD]

Welcome, I saw your "racing issue" thread, Have you ruled out a vacuum leak?

 

[Gray88]

I haven't ruled it out, I'm just not sure how to proceed. Any advice?

 

[HEAVY_GD]

Try this:

 

[verlaryder]

What happens when you turn the idle speed screw counterclockwise? Or are you saying you already did that? The aux air valve is generally troublefree and any deposits that may form in it actually lower the idle speed rather than increase it.

I think the factory manual has a spec for the dashpot setting rpm speed so if someone ever fiddled with the dashpot, perhaps they messed up the setting speed. And perhaps you could readjust it using the procedure outlined in the factory manual.

 

[Gray88]

@HEAVY_GD - Thanks for the info. I will check it out.

@verlaryder - I haven't messed with the idle yet. The problem started intermittently and has generally become worse. I haven't messed with the DP adjusting screw, since when I push the DP plunger down, (out of contact with the throttle valve) the idle remains the same (too high). I assumed something else was the problem, so I haven't adjusted it yet.

Good to know about the aux air valve being generally trouble free. That is an expensive part.