CONGRATULATIONS! You have just joined the group of roughly 170,000 owners of a shiny, but expensive, lawn ornament known as the infamous "Intrepid 2.7."
There are hundreds of websites that address this issue. To sum it up, the Chrysler (Mercedes-developed) 2.7L. v-6 is a piece of JUNK! And it is not repairable.
Do not attemp to rebuild it, have it rebuilt, or replaced with a new or used engine. You have three options. After 25 years mechanical experience, including working on many 2.7L (acting solely on customers' requests, and not by choice) , I have concluded that these are the best options for any Chrysler with the
2.7L. 1. sell the car (running or not) IMMEDIATELY and eat your loss; 2. drop a 3.2L or 3.5L Chrysler where the 2.7L used to live. or 3. Let the car sit there. Whatever you choose, if you do any of the above 3, you will get the desired results. If you still decide to replace or rebuild the 2.7L (always amazes me why anyone would do this, probably for the same reason as to why they decided to buy the car in the first place without doing any prior research); it will fail again, guaranteed!
If you decide on option 2, 3.2L engines are readily available with low miles (from accident vehicles) for around $500; any reputable mechanic should be able to drop it in for around $500-$750. Then you will have a car that will be as reliable as the next (non-2.7L equipped) car on the road, with proper maintance.
I hope this helps. I'm sorry I don't have better news for your situation.
Here's a website, a good start among the hundreds available, that will shed some light on this widespread problem, one that Daimler-Chrysler still denies.
John