88 K5/V10 Blazer 5.7 tbi 1227747 AMUR
Idle and Map sensor voltage both surging.
I can and did try adjusting TPS varying from .54 to .75, the best running was around .63 however it would dive, bog, falls on it's face or looses power when trying to go from 75% to wide open throttle.
IAC counts are 40-56 (depending on TPS) in park and are always 145 in gear.
BLM stays 128 most of the time.
The idle was set to 525 in gear with the IAC closed or fully extended and unplugged. The other readings were after re-plugging in the IAC.
I am kind of assuming that IAC 145 in gear means it wants more air? In which case a higher base idle would bring the IAC down? Is that correct?
Timing is set at 0. Engine is stock and has no modifications.
I did notice the MAP voltage goes up and down when the engine rpm surges up and down. Does that indicate a vacuum leak and if so how do I find it?
The only adjustable variables are base idle and TPS, so I am lost on what is out of adjustment?
I live at 5900 ft. above sea level, so it runs at high altitude.
Any help is very appreciated.
Thanks, Chris
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