So I picked up my '89 the other day. This is my first Jeep, and my first real project car. It has the 4.0, the selec-trac, a fabricated steel bumper, a new radiator, and power everything. All for $500.

But right now, it's got problems that need solved. Odometer reads 340k, but I was told it had an engine rebuild within the last 100k. One of the doors had a window broken inside of it. I just did a very minor tune up. plugs, oil, new wires, air filter, and a valve cover gasket.

However, The idle is very rough. It fluctuates between ~700-800, but dips down to ~500 for about 10 seconds before firing back up again.

This will hopefully become a thread that shows huge progress over the next few months, but this is where it has to begin. Where should I start with making this engine run healthy?

I'll post pictures when I'm not posting from my phone.