Exhaust Leak Causing Loss of Power

[bronco2blue]

I have two broken y-pipe to manifold studs on my 1994 explorer, one on each side of the y-pipe. There is still one stud holding the y-pipe in on each side. I can feel air escaping from the y-pipe flange and I can hear a hissing noise. I have no throttle response past about 2500 RPMs. The motor just boggs down and all I can hear is the air leak hissing. The leak is right before the o2 sensors, so is this exhaust leak causing my complete loss of power?

 

[bronco2blue]

The problem goes away if I unplug the o2 sensors. I'll drill out the broken studs and replace with new bolts and then I'll see if that fixes everything. Seems to me like the exhaust leak is making the o2 sensors malfunction.

 

[Big Jim M]

What most don't know is that the pressure at the Y pipe goes both ways! There is as much time spent sucking air INTO the manifold as there is pushing exhaust OUT! That air going into the pipe can easily burn a piston.. In your case it is confusing the ox sensors as well. By all means secure the seal at the Y pipe as soon as possible.
Big Jim

 

[bronco2blue]

I replaced every stud with new bolts except the outer stud on the drivers side y-pipe flange. My drill bit broke off inside the stud, so I still have an exhaust leak with no bolt there. I'm gonna try putting a clamp on the flange to hold it tight. I'm also looking into putting a gasket there, similar to the one between the muffler and int. pipe. I need to get it done because it's my DD. If this doesn't work I'll either take it to a mechanic to have it worked on or order pacesetter headers. I just want to avoid drilling out that cobalt drill bit.

 

[Andy D]

I use a small tweaking screw driver to back out broken bits. Tapping the side of what ever the bit is stuck in will help.

 

[bronco2blue]

I bought a clamp for it so seal up the leak and the truck still runs like crap. I'm hoping the timing chain didn't jump a tooth. I accidentally rotated the crankshaft backwards when removing the flexplate during the tranny swap. Could this mess up the timing? I also unplugged a wire harness during the swap by accident. Turns out it was a fuel injector harness. I connected it back up but maybe i didn't lock the harness in all the way?