Engine turns over but does not start

The car listed above was in storage for 15 years. The engine was rebuilt. When starting the motor it turns over, but, starts for only 3 to 5 seconds. It sound as if was running on 2 or 3 cylinders. Their is good compression and fuel. I was told that it might be the (PTU) Power Transistor Unit. Where is this unit located? Do you think that is my problem? Spark plugs are new. Thank you, Rowland