Just a thought, guys. I think it was Rebel who gave us that little 'tech info' on off-road H-pipes and how they affect HEGO sensors. I welded in the 'stops' he showed us how to make, and it REALLY made a difference on the low and high ends for me. They're basically dome shaped pieces of 16ga sheet metal welded into the H-pipe three inches after the HEGOs to create just enough backpressure for the sensors to get a reading. Mebbe this is what we need on the full lengths??? I want to know, too, since I'm going to be putting BBK full lengths on my Notch with the rest of my planned mods this spring. Oh, if your wiring is even a little messy, or not connected completely, yes it will throw a code. I had a little corrosion in one plug and it threw some bad signals. Hope this helps.
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Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch 