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This car just runs funny sometimes. It'll be at idle, like 8 or 900 rpm. Open the throttle and it slumps down to about 500 rpm and then revs from there. Once it starts revving everything is great.
It's just that one time, from idle only, that this occurs.
Any ideas?
o and, it's the 5.0 h o setup.
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I believe that even the older speed density systems used an IAC valve. And I know that it's secondary function is to ensure a smooth transition from idle. Idling at 900 rpm seems high also which could point at the IAC as well.
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1986 GT-X303-289 heads-1.72 rockers-RG 4+1 Trans.
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I had already cleaned out the IAC as well as I could twice. I thought it made a difference the first time but I couldn't tell the second.
I replaced it.
...Finally got around to checkin' codes via KOEO. 22 and 32 were the only ones present.
so 22= Manifold Absolute Pressure/Barometric Pressure Sensor Out Of Self Test Range (O,M,R). I replaced that bad boy and the car seems able to correct its idle as opposed to wavering between 500 and 900 rpm when started(this was an intermittent symptom). Throttle response seems fine now, actually.
but 32= EGR Valve Position/Pressure Feedback EGR Voltage Below Closed Voltage. 0.24 volts (O,M,R) I'm not sure how to interpret this; if it means the EGR is stuck shut, then that's probably desirable, eh? I've seen that it's a pretty popular move to eliminate this system altogether.
The car does still seem to have to rediscover some kind of balance in order to idle properly immediately after a start sometimes, and I wonder if that's EGR related or if there's something else going on that wouldn't be present in the diagnostic... memory?
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Last edited by baddestmofo; 09-20-2009 at 11:44 PM.
Reason: a detail
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speed density fuel injection behavior
