Are you saying that one of the AIR hoses that connects to the check valve on the exhaust manifolds was leaking? If so, it could have been melted by exhaust getting past a faulty check valve. If the valve is stuck open, it could be pulling air into the exhaust during normal driving, and causing a false lean condition at the O2 sensor, making one bank of the engine run excessively rich... perhaps enough to allow enough fuel into the exhaust to make it pop when the fuel ignites. You might want to check the plugs on the bank of the engine where you had the leaking AIR hose. Might be carboned up from running rich.

That line is the vacuum source for the EVAP canister purge system. That's basiclly a huge vacuum leak if the hose was cracked between the throttle body and the purge solenoid.
You describe it as connecting to a "silver box" on the valve cover. Almost sounds like the line may be hooked up wrong, because is should connect to the solenoid, which is black, and mounted on a bracket on the passenger side of the intake manifold.

 

Sounds like a few things are wrong. When I taped the hose to the TB it would not start and blew a lot of smoke (carbon?) out. I pulled the hose away a little bit and it started up again. It ran a little better until it warmed up. The exhaust also does not sound the same. That was my first clue that things were going down hill.

Unfortunately, it is my DD, so I need to get it back into shape soon.

Thanks for all the help!

 

check to be sure your cats arent coming apart and clogging up the exhaust i had that problem threw all kinds of parts at it until one day i revved it a little and heard something going down the exhaust it was pretty funny

 

I do have an occasional rattle, but it sounds like it's also in the engine. I have not checked for cat rattles. I'll try that, too.

Injuneer- my bad. The hose does connect to a black box, not silver. The elbow hose on the other side of the engine was connected to a silver pyramid thing and into the drivers side of the engine. I wiggled it and the rest of it fell apart. The bottom was already gone. That was my exhaust leak.

I heard air rushing somewhere on the passenger side when I found this smaller hose that was rotted out. I don't see any more messed up hoses, and cant hear any more rushing air, so could these 2 hoses be the cause of the problem and I did not find it until it did more damage?

 

Was this the "silver pyramid thing"?

http://shbox.com/1/diverters.jpg

....but they are also black.

 

That's it, but mine is silver. Must be burned up?

 

Sounds like that check valve may be faulty, and not blocking exhaust gas from flowing back toward the AIR pump. That would account for the damaged rubber elbow. It might also account for the poor performance, due to air being educted into the exhaust under some operating conditions, and throwing the O2 sensor and the A/F ratio completely off.

 

And why I had exhaust coming in the car. Would a new AIR pump and 02's fix the problem? Assuming nothing else is damaged. Possibly plugs?

I have an LT4 hotcam and the idle was normally just under 1000 rpm's, with a few revs over/under every five seconds or so, but now it bounces between 1000 and 750 rpm's and it just does not sound right. It backfires when I touch the gas to get moving. It will still accelerate good when I hit the gas harder, like passing on the highway, but I get an occassional backfire at that, too.