I have a 1996 Volvo S960 wagon with 260,000 miles on it. After purchasing it we drove it 3 months before my wife ran it hot and put the engine to pasture. I found a wrecked 1997 960 with 115,000 miles and purchased it for the engine so I could bring the wagon back to life. I had a mechanic swap the engine out for me but now it won't run for over 5 minutes without dying. When the engine was first swapped it ran for about 15 minutes till it ran out of gas. Unfortunately, the gas tank had trash in it so a thorough fuel system cleaning was done. Next, the car was started and ran for 5 minutes before it died again. This time, the ignitors went bad. We swapped these out with the ones from the original engine. The engine then ran for 5 more minutes before it died again...once again the ignitors went out. I suppose my question is, could there be a computer conflict between the 96 and 97 model engines? Could it be a voltage regulator? I'm open for any suggestions here..

 

Sounds like it has something to do with the car getting warm, maybe the MAF. Try unplugging it and seeing if it will run with it unplugged.