I got two turbo mufflers on my 86 bronco II 2.9, that's it. The O2 senser is in the same place,didn't move it. It's working good, as far as I know. From time to time the truck idlas very low(about 6-7K RPMs) then it straitens out. It does this while I'm stoped. The longer I'm stoped, the more it does this. At driving speeds I can fill some loss in power at times. Agin, it goes back and forth. The first muffler is about 13"-16" from the Y-pipe. The secend is about 20". I've stated to thank the deffence in length may have something to do with it.I've beentold myback pressere is wrongorI've got a flow reversion problum. I don't know.Ifone of thisis the case, I've thought of one of two ideas to fix it.go withtwo Flowmaster Hushpower II resonators. Their size would let me get them up close to the Y-pipe and have them at the same length from. After that, maybe some glasspack.Or, go with one of the old cats and add a thrush"single in-duel out" style muffler. This one would be the cheapest.Any ideas?[/align]