1994 ford taurus idle problems

I recently had a no start in this vehicle. here's what been done Lots of parts some were bad some were questionable at times the car would let you
pull codes first thing in the morning only once then you couldn't access codes again till car sat for awhile even had a mechanic try hooking up his snap on scan and he couldn't connect to the computer. 1) ignition module( last time three years ago this was problem) 2) cap & rotor 3) pick up coil in dist. 4) spark plugs (first set fouled out) 5) relay module on rad. ( fan and fuel pump ran constant) 6) fuel filter (fuel pressure 30 psi when running 40 psi on acc.) 7) coolant temp switch (questionable ) 8) act switch ( burnt and carbon fouled) 9) oil sending unit (leaking) 10) maf sensor ( seemed reasonable 149,000 mile on old one) 11) tps ( open no res. between post when off car) 12) Iac motor ( frozen cone and shaft even tried cleaning ng) 13) eec computer ( last component replaced car started up runs good fan and fuel pump run like there suppose too fuel two sec shuts off fan up to temp. then runs) Car now runs idles high, yes I did mess with idle screw during attempt to get vehicle running when it would idle poorly used a tank of gas just idling in driveway. It seems the computer was shoot from the beginning but now all new parts. why would engine idle faster than it should. Book says eec controls idle. with all new parts where should I look or do next. checked al vacuum lines replaced cracked or bad looking lines so no vac leak egr valve moves removed and cleaned applied vac can hear valve open and close. Cleaned throttle body scan codes are 536 and 538 .
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First the codes arent significant... they are KOER test, and probably there because you didnt goose it or push brake at proper time
AssuMe the ENTIRE IAC is new?
With IAC plug disconnected, still idles high?
With all manifold vacuum ports, except port for Fuel Press Reg, disc and plugged?
If idle still high..(assuming you tried to return stop screw to orig pos) then are you sure throttle plate isnt binding, somehow?

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Seems to me that you still missed several places where vacuum could be leaking. It's not just vacuum hoses and fittings that can leak, but anything that uses vacuum can leak. The best way to check everything is with a vacuum pump that has a gauge, such as the MityVac. The EGR valve is a good start, but you can get a high idle if the EFE solenoid is leaking (partially stuck open), there is that other vacuum line that goes into the dash and is used for a HVAC flapper. Plus it could be the power brake booster or cruise control.
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Howbout a squirt bottle with water and spray everything thats vacuum related
The water will fill up the leak/crack for a second and will make the idle change

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Water will not seal a vacuum leak at all- where did you get this nonsense? The water will simply be drawn into the combustion chamber, just like water through a straw; Use a propane leak detection device instead. This is a tool specifically designed to release a small amount of propane gas through a hose that can be directed to the potential leak source. This artificial enrichment will show an immediate reaction to the idle when a leak is found. And yes, it is safe; the proper tool will not put out enough gas to be any kind of hazard.

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