Hello! My 2002 Mercury Cougar V6 Automatic idles lean when in drive and reverse at a stop. In neutral it idles perfect.
More Context: When the engine is warmed up the lean idle stops but the rough idle occurs a few minutes after starting up. The rpm sounds like it's going to stall but it doesn't. It does not trip any codes. It idles normal around 800 rpm and then it dips to 650 sporadically at a stop. I recently replaced the fuel injectors, sparks plugs, intake gasket, fuel filter, EGR valve, and even the IACV, but it still has this issue. The fuel pump was replaced from that 2004 recall, and I swapped the air intake & MAF Sensor from another Cougar and no fix.
I would appreciate any advice. Long live the Cougs!
Update: [F68E-6758-AE / M536K is a part that I may or may not need to replace to fix the vacuum leak. I wrapped tape over it & the idle is still rough]
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