Yesterday was the third time this has happened to my 89 240 in the last 5 years. When driving the car while the outdoor temps are near 100 degrees. the car will start bogging down. The more gas you give it, it just sputters and dies. If I pull the car over and let it sit for an hour or so, it will start back up. I don't think it has anything to do with the car actually overheating. I recently replaced the thermostat because it was getting stuck open and running too cold. Since then, the car's temperature gauge has been working just fine. I use to own a 2 stroke motorcycle. It reminds me of how it would run if the oil mixture was too rich.

 

How much gas was in the tank? Less than 1/2 full? If so, could be a failing in-tank fuel pump. Take a look at this site for diagnosing problems with fuel pumps:

In the Tank - 240 Volvo Tank Pump and Sender

 

It was half full. I've considered the fuel pump might be failing. Curious as to why the outside temps would cause the issue. Thanks for the reply.

 

Gasoline gets thinner and harder to pump the hotter it gets.

As a side note - have you checked your air box thermostat? - when bad (every few years) they get stuck in hot air mode - pulling heated air from around the exhaust downpipe - not good for the air mass meter.

 

I will look into this. I'm looking to replace the in-tank fuel pump at the moment. Thank you.

 

I spoke with a friend who drives a different kind of car but he explained, it was the same issues he was having that led him to replace the fuel pump. The fuel getting thinner makes sense.

 

It may be the fuel pump but the link I sent you has a nice writeup that shows you how to check whether it is functioning properly. I would only replace it if you find it to be faulty as some of the replacement parts you buy these days are not as durable as the originals. My last 240 had almost 270k miles on it when I sold it a couple of years ago. It was 27 years old and still was running on the original main pump and the pump was quiet as ever.

 

Also, bogging down may be caused by another part which under excessive heat malfunctions, such as the MAFS, the ECU, etc.