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06 LGT idling stalling A/F issues

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Hello, I've got an 06 legacy gt 5mt. I got it in trade with a lot of mods already done to it. I know not the best way to get a car but I pretty much got it for free soo... The issue I am having with it is, when the car is warm the idle drops very low and the car will stall if you take your foot off the pedal. I tried the idle relearn process and seemed to work until I pulled out of my driveway and stalled at the first stop sign then the a/f started bouncing around from like 11-17 with a low rough idle and would stall if you took your foot off the pedal. I parked it after that, not wanting to do damage. I'll list the engine mods I know below.

catless UP & DP

nameless cbe

cobb intake


BNR 18g

grimspeed ebcs

"custom" tune

unsure of what injectors and pump are in it.

I am thinking of picking up an AccessPort so I can redo the tune and maybe change out the injectors so I know what they are.

Mainly just looking for help on where to start with the issue. I can try and provide more info if needed.

Any help would be greatly appreciated

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Willing to bet you have a large vacuum leak. Smoke test would be ideal. Consider the price of a new tune right away when you consider picking up an accessport. Installing the accessport will remove whatever tune is on there right now and you won’t be able to drive it without a custom tune.
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Alright, I've cleaned the MAF, found and fixed a couple leaks in the fmic piping, connected a rubber vac. line on the drivers side intake manifold, and installed two intake manifold bolts that were missing. Drove the car and the idle is still dropping really low and stalling along with the a/f ratios bouncing around. Seems that as soon as I touch the gas pedal is when a/f jumps around and rpms stumble. When I first started the car after fixing these things the idle was slowly creeping up to about 1500 and then I barely touched the throttle and it dropped really low and almost stalled but caught itself and idled back up. Backing out of my driveway and going to the first stop sign seemed fine but as soon as I almost came to a stop off the throttle it stalled. I got into boost once just to see if the power was still there and it is, feels fine and a/f read fine in boost. Just stop and go, barely on the throttle is what seems to be causing issues.
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Do an ECU reset either via battery or btssm. Then start it with all accessories off. Don’t touch the gas, let it relearn idle for 8-10 min. Then drive. If it’s still trying to stall, go look for more vacuum leaks.
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Bad MAF? Is there a TPS sensor that may have konked out or needs a calibration/relearn? Being around Mustangs a bit I know the TPS can make for all sorts of issues.


Sent from my moto z3 using Tapatalk

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