After replaced IAC still wouldnt idle so installed IAC spacer and it runs pretty good at 12 BTDC, TPS is set low, fuel pressure about 35-40 psi.
Only thing now is when stopping, put the clutch in and brake, when the RPMs hit bottom it will die if I dont feather the gas. Tried to adjust IAC spacer screws to let more air in but then the idle gets worse.
sounds like you are close. Typically with it dying like that it would be the IAC clean or replace. The signal to it should be a square wave, forgot what the frequency is, but they vary the duty cycle to get it to open more or less. I would think that one lead would be signal and the other ground, rather than getting it off the block. How are the HELO sensors in the exaust? they can get contaminated if you use silicon gasket material. You should be working closed loop. Good luck, and let us know what you find.
Well, replaced the IAC with no spacer, no good, added spacer, then better. We figured out that the IAC holes on the new ford racing throttlebody are smaller than stock!!! couldnt beleive it, put the stock TB on and now it idles, though rumbly because of the heads and cam. it looks totally sweet and hauls a55 too. still have to try a BBK
70mm TB and get the smog pump pipe welded shut on the exhaust and see how much better it gets. but its definately a highly modified stang now.So Id have to say there is something to those IAC spacers, FR TBs suck, and the bbkssi intake probly outperforms the trick flow and looks totally killer but its a totall PITA to install. though like anything, once your done and familiar with all the solutions you came up with you can tear it down and put back together almost blindfolded.
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