Vehicle repair taking 4 months

I purchased a 2001 Dodge Dakota about 2 years ago. About 5 months ago I found out the hard way that this truck has a major issue with sludge build up. (That should be a class action suit by itself, if you google Dodge Dakota and sludge you will see hundreds of people with issues and Dodge not covering the ones still under warranty) I needed to have my engine rebuilt and I took it to a local shop. They have had it for 4 months now and they have stopped taking my calls about when it will be finished. They have worked on it but it is not done and I don't know when I will get it back. They originally told me a few weeks. What legal action can I take?

Based on what you say here, you could file suit against them (or at least threaten to do so) in small claims court or in regular court; filing in small claims court is easier and requires no attorney...you could try to collect all of the costs and damages that you suffered due to their behavior... You may also report them to your state attorney general's office.