Rough Idle and Gear shift

[Joerocco]

My 2004 Jeep Liberty has 140K miles on it and when I first get in it and drive if I accelerate slowly I get a thud sound and then the jeep jerks forward. One that happens the jeep runs fine. It also has a bit of a rough idle. I thought it might have been some bad gas so I ran to below 1/4 of a tank and filled it with high-test. Now here is the kicker! I brought it into a Jeep/Dodge/Chrysler service department to be looked at and I was told that the Jeep is too old with too many miles on it and they won't service it. This is a two owner Jeep with full service records through Jeep is in excellent condition and they won't even look at it saying parts are too hard to get! Has anyone ever experienced something like this?