So...is there some kind of dark magic involved in conjuring up an exhaust flange gasket? I found the exhaust leak, passenger side, between manifold and exhaust pipe. People are standing on street corners selling exhaust manifold gaskets for my car but the flange gasket appears to be a unicorn. Is it the same gasket for other models that have the 4.2? Any suggestions where to source one? I'm hoping this exhaust leak accounts for some of the quirky live data I've been seeing. O2 sensor jumping around, ect...

 

The bottom of the exhaust manifold is 'spherical' and the cataverter/downpipe is concave to accept the curved part.
There is no actual separate seal.

 

That would for sure explain why I couldn't find a gasket. The odds of tightening the bolts without breaking them... Thanks for the info.

 

With all the random DTCs you're finding stored, the first place to begin sorting things out is by checking the available battery voltage. Many random instrument cluster warnings, DTCs, and other electrical 'gremlins' are caused by insufficient available voltage.

With the ignition in the off position for at least thirty minutes, use a voltmeter to determine the available voltage. There should be a minimum of 12.6 volts indicated on the voltmeter. If there is less than 12.6 volts showing, charge the battery for five hours at 2 to 5 amps and retest. If voltage is still below 12.6 volts, the battery is suspect.

 

2 month old battery. Shows 12.6 volts after sitting for a couple of hours. Passed load test.

 

you can have a gross exhaust leak at the collector and you'll stay out of restricted performance long term trims

i have deep gouges in my left collector and it's still not enough to push LTFT over 17.5

 

Good to know. Thanks.