I've got a 99 Sahara with 143k. When I purchased it the idle would go up and down (pretty dramaticly) until warm. I replaced the cap, rotor, wires, plugs, tps and idle speed thingy- also cleaned the throttle body.
Now it runs great, EXCEPT sometimes for maybe 15-30 seconds it will act as though it's running out of gas. I can put it in neutral and the motor will rev fine, but in gear it bucks. This most often happens if I turn the motor off, then restart- after about 30 seconds this will happen and once it stops (again, after 15-30 seconds) you can drive for 8hrs, no issues.
I am planning to replace the map sensor and the O2 sensors. I'm running a quart of ATF now as well as Seafoam.
What might cause this?? Thanks in advance!