weird idle problem after knock sensor replacement.

[anti_flag_army]

So my grandma asked me to finish fixing her xterra after she had some "friend" work on it and sucked at it. I get there and the sensor has already been replaced, the lower intake is on and all i need to do is replace the upper and hook everything back up.

After all day of trouble shooting problems and trying to get it running right we think we have it right. On the test drive its fine, but then it starts sputtering at idle and anything below 3k rpm, after that it will rev smoothly, but anything below it makes it sputter and struggle to hold idle. No codes are present. The only issue we had when putting it back together, was we found a vacuum line that had a broken end on it, but i could not find ANYTHING that it would plug into. it was a small line under the throttle body.

The problem only showed up after driving it for about 5 minutes of smooth driving. any help would be great!

[RT]

That vacuum line is most likely the problem, find another exterra to trace it or got to dealer have parts guys pull up micro fiche and trace where that line goes to. Skip the manuals at parts stores most have electrical schematics but not vacuum line ones. Look under hood some cars have a basic vacuum line schematic. Or try googling vacuum schematics for exterra.