Alright, drive home, approx 26 mile drive. Car sat for 1 1/2 hours. Started it back up and let it idle. After about a minute, the exhaust would pop slightly, and then the idle would surge just a bit, then everything would be normal....then about 2-3 minutes the same thing would happen. When kneeling beside the driverside front, I can hear a loud, deep knocking sound coming from the bottom end of the motor. This didn't sound right, or good. What does all this mean? I do have an exhaust leak on the header/y connection on pass. side. Besides that, everything looks in order. Thanks for any help.

 

Holy crap I have the exact SAME thing happening to me!
Someone has to know what is going on!
OK here is my theory:
I have an exhaust leak at the header on the passenger side, I think the O2s see an extreme lean condition on that side and add a bunch of fuel that fuel gets burned in the exhaust causing the popping. The knocking I don't know what that is, someone surely must know.

 

Ummm, spun main bearing?

 

Depends on the sound of the knocking, but "loud knocking at bottom end" sounds like spun bearing(s).

 

Ok. Not knowing as much as most on here, what exactly does that mean for the life of the motor. The car is strong, with really no other things that make me ask 'what the heck is that!'. I have no SES light or anything. What does it do to the engine driving on a spun bearing? How does a spun bearing happen? What exactly is a spun bearing! Obviously there is alot of things I don't know about in regards to this. The loud knocking has just popped up enough that I hear it.
Thanks

 

I have the same thing too but my grandpa who has been a mechanic for 50 years said i was hearing the exhaust leak and that is what i thought was a knock. That might be what you are hearing too.

 

I get that sound when it is idling like crap. I think it is the throwout Bearing, the main reason why it isn't a main bearing is because when it is running in open loop the car idles fine and there is no noise.
Maybe the exhaust is leaking cause the 02s to pull fuel and causing the engine to run lean thus detonate. Who knows.

 

The donut between header and Y is almost gone on pass. side, and I assume the other is the same. Ordered the donuts, just have to install. I really only hear the knock at idle, and I rev'd the engine from the front of the car and didn't hear anything like I've heard from some of the other posts I've read and listened to. ALSO, when kneeling down, this knocking is intermittent, it's not all the time. Throw out bearing???? I'm going to try to idle it and push the clutch in/out to see if this knock goes away. BUT, this motor is starting to make noises. Not good ones.
Thanks