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T77911S T77911S is offline
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Join Date: Oct 2006
Location: MYR S.C.
Posts: 13,546
the AAV and the AAR do not effect performance unless they are bad. IE leaking unmetered air.

you have an air leak if you cant lower your RPM. the air leak can be before the TB, but it is after the AFM. are you sure the TB is in good working order?
i have been fighting air leaks for a year and just found my big one.
i had a bad hose connecting the IC up pipe from the turbo, my WG was leaking. my intake manifold was leaking. (i may have created that). my DV was leaking vacuum. every now and then i break an Oring on the throttle body putting the IC back on and dont know it til i take it back off. also check the long studs that screw into the manifold.
one other thing. check the vacuum line from the manifold to the brake booster. you should be able to pull a vacuum on it and it hold.

with a leak my cruise AFR was in the 15's, sometimes 16's. i could set the idle to very rich and it liked it. i also had my idle set to 850 rpm and it liked it.

with leak fixed my idle dropped even more, to around 600. but then my cruise AFR is in the 11's and 12's but the car LOVES it. GREAT throttle response at low RPM and off boost. but my idle mixture was now in the 17's.
long story short (too late), i have/had the same issue when letting off the gas after trying to get good idle AFR's and cruise AFR. RPM's drop to 0 and bounce back up. leaned out the idle some and it is better so far. when the idle would drop to 0 the AFR was around 10, then both would come back up with AFR settling at 13. now it is 14.
i have also done some things i dont suggest. i lowered the fuel volume out of the fuel distributor. DO NOT do this. if you suspect the FD is bad, send it off.
cruise AFR is 13.4 to 14. it really does not like it this lean.
i am not sure about my system pressure. i ahve 2 gauges that read 2 different values. if the one gauge that reads low is correct, that would cause me to be rich.
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Old 11-05-2014, 10:03 AM
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