Ive viewed about a hundred different threads on this so far and nothings helped yet so I'm gonna give this a shot. I have a 2001 Jeep XJ that recently failed its inspection due to a large evap leak. also about 3 weeks before the inspection the jeep started to have a semi rough idle and there was a knocking/sputtering noise in the engine bay.when accelerating you could still here the sound but once the engine got completely warmed up it wasn't as pronounced. if i placed my hand under the headers directly between the pre-cats i could feel air coming from above and to the left of my hand. i guessed and then was told by the people who did the inspection that it was most likely a crack in the headers (mine don't have the flex section). All fluid levels are fine, pressure and temp are fine for everything, no odd smells, and it starts fine (just a little rough on those extremely cold mornings) so im wicked confused, i pulled the intake manifold and the headers and have yet to spot a crack in either of them. Any ideas what this could be??

 

nobody!? come on guys i'm dying here

 

I would have guess a crack also but if there is no crack then maybe a bad gasket where the exhaust manifolds join the down pipes?

 

Have you checked your evap canister near the fuel tank for cracked hoses?

 

check the mounting surface of the exhaust manifold for flatness.

 

all the hoses are fine, no cracks.

the surface on the engine block seems to be perfectly flat

 

nope, i meant to say that my hand was above the precats but in between the two of them, sorry man my bad

 

The reason I'm asking all of this is I don't want to drop $300 on new headers if it just needs a new gasket

 

was the exhaust secure to the headers? j/c

 

They seemed to be. All four of the bolts were pains in the *** to get off

 

Was there a "Donut looking ring" between the headers and exhaust when you got them separated?

 

nope just the bottom flanges in this pic and then the bottom of the headers.

 

i havent researched it yet for the jeep but usually there is a "Donut Ring" that goes between the headers and exhaust, to account for flexing between the two. not saying thats the case but just an idea i had. Also maybe a previous owner removed the header before and forgot bolt and your missing one?

 

Yeah I looked into it and alot of people with 01's don't have them

 

I just ordered my new headers because there bound to crack anyway but I also got all new gaskets flanges and hardware for everything so no matter what ends up being the problem it will all be replaced