The oil has recently been changed but is a little darker than expected. I drove it home last night and the check engine light was off. I live on top of the mountain and was following a car going about 30mph in 3rd gear, the Jeep felt like it was going to stall out. The check engine light started flashing, I geared down to second and drove it about 100 yards and the check engine light went off and it started running fine to the house. When I geared down to second I could tell the HP dropped. It does have a little rough idle.