Hi everyone. My car seems to run like a bat out of heck when it is cool, but when it is humid or hot it does not perform nearly as well. I have done research on this site, but can't find an answer. Help Please Thanks Fred

 

I have this problem too. The humidity doesn't seem to affect my car but the heat appears to.

 

Car is very sluggish in warm weather what could be the cause. I need your help Tech! I also have a small leak from power steering pump, how do you get to the clamps and how many hoses come off of the pump. Thanks

 

For the car being sluggish in warm weather is common and far more noticable with a turbo charged car. In winter the car will feel as it has more power. This is due to the fact that heat causes expansion so there are far fewer molecules in a given volume than at a colder temperature (refered to as density). The turbo charger is only able to push in a certain volume of air and in warm weather the air contains less oxygen molecules per volume (less dense). So the turbo is pushing in the same amount of air but less power is being created. Apparently the fuel mixture during summer and winter is also different as well, with the winter fuel being more volite than the summer which also makes a difference. You can add a bigger intercooler to help cool the air and make it more dense which should reduce the sluggish characteristic of the car.

 

^ What he said^ You can also ad an aquamist system or an intercooler sprayer if you want.

 

So that explains why the drive to work in the morning is better than back home in the afternoon

I also notice a difference in response when I have newly filled tank. Seem to drive better if I'm full compared to almost empty (like 1/4 left in the tank). Is this also normal ?

 

Thanks jott. Nice to know it's nothing out of the ordinary.

 

Could this problem with being sluggish be related to a faulty mass air sensor? Can you just replace the sensor? Check engine light is on and this is what the mechanic at volvo said the problem was. Any suggestions would be appreciated.