1985 Toyota Pickup Vacuum Gauge Readings

1985 TOYOTA PICKUP
75,000 MILES
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PCMENTOR29
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  • 177 POSTS
I hooked a Vac gauge to plenum and saw 17.5 in Hg at hot idle. My question is why would the needle slowly float between 17.5 and 18.0 in Hg and be sort of corresponding to an uneven idle? At 2500 rpm the needle doesn't move or vibrate at all. I am at 2100 ft elevation. Engine is 22RE 4 cyl FI. I have looked at several vac gauge charts but don't see symptom. Thanks for your help.
Jul 10, 2013 at 9:17 PM
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HMAC300
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it could be the idle air control valve opening and closing there is nothing wrong with that reading. if you want clean the throttle plate with choke cleaner on both sides an iac hole.
Jul 11, 2013 at 8:42 AM
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PCMENTOR29
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Thanks for your reply, I am going to see if the Aux Air valve is passing vacuum. It is the IAC on the 22re motor. It has one hose on the plenum and one before the throttle plate. I had the emissions tested and it is bad at idle still even though I put a heated O2 sensor on it. The idle is still uneven so I know there is some other issue. I will post when I have an issue to ask. Any ideas you have I will be thankful for. Thanks.
Jul 12, 2013 at 8:55 PM