I have a 2003 S40 with 108,000 miles on it. I was sitting at a red light the other day and all of a sudden the idleing went way down and the car started to spit and sputter like it was going to stall. I pulled over and sat there for about 5 mins and it did not do it again. but why do you think that happened?

I also have a 2003 Volvo S40 that was having idling problems about a year ago when the car had roughly 105K miles. I could start the car if I pumped the gas, but as soon as I took my foot off the accelerator, the car would stall. After the car stalled while I was driving down a busy road, I decided to go straight to my mechanic for repairs. The mechanic replaced the idle air control valve, and the problem went away. Recently, at 135K miles, the problem came back -- but I only had trouble in cold whether (the car wouldn't idle on a cold start in temps below 45 degrees). This time the mechanic diagnosed the problem as a gunked up fuel throttle body. To fix the problem, the mechanic cleaned and adjusted the fuel throttle body. I also have a 2003 Volvo S40 that was having idling problems about a year ago when the car had roughly 105K miles. I could start the car if I pumped the gas, but as soon as I took my foot off the accelerator, the car would stall. After the car stalled while I was driving down a busy road, I decided to go straight to my mechanic for repairs. The mechanic replaced the idle air control valve, and the problem went away. Recently, at 135K miles, the problem came back -- but I only had trouble in cold whether (the car wouldn't idle on a cold start in temps below 45 degrees). This time the mechanic diagnosed the problem as a gunked up fuel throttle body. To fix the problem, the mechanic cleaned and adjusted the fuel throttle body.