[cormac827]

disconnected battery for about an hour or two, plugged back in and issue persists.

It is a sort of sputtering around 40-50 when getting on expressway....when i pull back off gas, it goes away, it only persists if i really step on gas then it works through it. feels good driving local side streets etc.

[Machine15825]

Not sure. is the IAC off the 2.5 or a 4.0?

[ZeroGravity]

Bang on your cat with a rubber mallet or just grab it and shake it real hard. If you hear something clunking around, it's probably the core broken off.

Sometimes this can block the exhaust flow and cause your engine to stall.

[cormac827]

IAC is off of a 2.5l i believe, unless previous owner replaced it and didnt tell me. I did not replace the IAC yet, but it has no idle issues, only the issue stated when under strain/accelerating.

I will need to check cat, i looked for it once but did not see it haha...it should be right in front of muffler correct?

[Machine15825]

Uh, you said that you put a 4.0 throttle body on...... So that requires changing the IAC from the 2.5 throttle body to the 4.0 throttle body. Did you do that?

[cormac827]

sorry if i misled you! I just got a replacement 2.5l throttle body.