asmith

I have R350, 2006. This problem only happens in cold weather (temperature below 2 degrees Celsius) and also only happens when the car had parked overnight or for more than 24 hours. When I start the engine for first time in cold weather, the RPM drops very low and the engine gets very close to stop then immediately the RPM jumps high to keep the car running. This all happen in about 2 seconds. Again, this is only happen if the car had parked overnight or more than 24 hours in cold temperature. Even if I leave the car in a very cold weather for 10-12 hours after start, the engine runs fine. Another important note is that if I press the gas (even slightly) right after turning on the ignition ON this problem never happen. I have been reading about this problem and most of the comments suggest that there might be some water in the fuel line or in the gas tank. I used over 10 bottles of STP over the past few months but the problem still there. Any suggestions please

auto385

This is strickty an issue where the computer is slow to respond to rpm input. A proper scan tool may pick this up. It can be also that fuel pressure at first start up is too low. We are talking about the diesel right?

asmith

Thanks for your response. No it is not diesel and you are right I never thought about computer is show! I have iCarsoft MB II but it didnt pick up anything. But in the meantime, if it is computer problem why it does happen ONLY in temperature below 3 degree? and why it happen in this temperature only after the car parks overnight (it doesnt happen during the day even if you leave the car for 6-8 hours in a very cold weather). Same think about fuel pressure, I also measured the fuel pressure and it was good. But I measured it while the engine is running which is the case were there is no problem (as this problem happen only one time in the morning and then never happen again until the car parks overnight). Could it be the throttle valve actuator??