Originally posted by DemonSVT:
The only thing I can think of directly off the top of my head is it's because the Bank 1 exhaust manifold has a much higher flow rate due to it's better design.
If that is true, then why does the pre-cat problem happen to mostly older cars? Shouldn't newer cars have this problem as well (and throw CEL P0420)?
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
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