rough idle

[cheapcherokee89]

would a BAD exhaust leak at the manifold make a 4.0 idle rough?

 

[Chris_Keziah]

Not that I have ever heard of. I would check the ign sys. Plugs, cap and rotor. Worn cap and rotor can cause a rough idle, that also check the plugs, if they look ok then just clean them up and REGAP them. Not sure what jeep calls for but usually 35 thou. (.035). But get that exh leak fixed it can cause some pretty bad things to happen if it gets worse.

 

[3DCrawler]

Yes it can. With the exhaust leak bringing in fresh air the O2 thinks the engine is lean and will put more fuel in to try to correct what the O2 is reading when in fact the engine doesnt need anymore fuel.

 

[hadfield4wd]

The exhaust manifold and intake manifold share a gasket. So chances are you have na intake leak as well.

 

[cheapcherokee89]

okay thanks. will fix that then see what happens