86 2.8l high idle

Hey guys trying to figure out an issue here. A freind got a 86 xj with the 2.8L V6, that is idling around 1800RPM. On the firewall it says that its principle purpose is high altitude, from the factory. We live at about 20 feet above sea level so I forsee some sensors being swapped in the future. Does anyone have any info on these I am used to the 4.0 issues or know where I can find the info. Thanks in advance:cheers:

I would check the vacuum lines. The 2.8L has a mile of vacuum lines attached to it and if ther is a broken or cracked line that would cause a high idle. I swapped the carb and intake for an edelbrock 2piece intake and a Holley 390cfm 4 barrel carb. and got rid of most of the vacuum lines.

The whole damn 2.8 and do a 4.0 swap

The intake manifold bolts come loose, they did a redesign a few years later. Other than that a vacuum line is likely. Re torque the TB also, the gaskets shrink.
Sometimes re tightening the manifold bolts is enough, but it's also possible the gasket has shed a few chunks.