LOL, another rough idle question... Oh boy

[travlincub321]

Ok

So my 2000 Exploder with 137K on its slightly rattly 4.0 SOCH has the rough idle issue, BUT, only does it when it is HOT OR WARMED UP.. When its cold or just starting, its fine.... IF i can keep the RPMS above 800-1000, its fine... Replacing the IAC tonight did help some (got rid of the noticeable vibration), but its still there.....

I can here what sounds like a leak from the back passenger side of the engine...

I know these motors sound like thy have a perpetual vacuum leak anyway, so IDK if its my rig or not..

Does this sound like the dreaded intake manifold gaskets or the pcv valve (which IDK if its been replaced) and tube?

 

[RobertE]

I have a similar issue that when i press the gas hissing in the same place gets louder on the highway. I bought an upper gasket set to clear up the issue.

Try the carb cleaner test by spraying carburator cleaner around the engine block to see if the idle improves. If it does its probably a gasket worn in the location sprayed.