I havent used my car for 4 days and it has been a bit cold here in southeast michigan. Today is about 45 degrees which is fine. However, I pressed the start button my 06 GS300 with 66k miles, and the engine roared and had spiking RPMs from 500 to 2,000 up and down several times and it felt like the engine was struggling for fuel. I turned it off and restarted it and same problem for 5 secs so I shut it off. There was some grey smoke coming out from both exhaust with fumes. I then let it sit off for few minutes and restarted it for the 3rd time and it started up normally. What was this problem??? Never had this before. The instrument lights were fine so I doubt it was the battery.

 

May need a injection service or throttle body cleaned, try using a gas additive

 

I think I know what your talking about, cause my car when it's cold will spike at high RPMS and then it automatically goes normal i don't think its anything to worry about on mine but your sounds a little more serious how long does it take before it finally runs normal. cause after about a minute i hear the engine go from high to low rev's

 

I've had the same spike on start up, after the valve spring recall was performed, but without the smoke. My car will usually run for about 5-10 seconds, then spike to 2k+ for a few seconds, and then come back down to normal. My dealer says they won't do anything unless there is an error code.

 

The problem was severe that day but it has not happened again since then. So I am not sure what to do. If it does happen again I will have the dealer check out the throttle system and fuel pump and rails.

 

Hmmm I've experienced it spiking before but I thought it's just due to the colder temperature so the car's trying to warm up more aggressively.

 

Mine used to do what you describe, where the idle would hunt up and down but only when started for the first time in a day after sitting at least overnight. It still does it _slightly_ sometimes, but it has improved a lot since the valve springs were replaced and the top engine cleaning. I never noticed any odd smoke when it did that, though.

Rarely, I will press the start button and the car will just die after it seems to catch but starts right up when I try again. I think that may be caused by my getting lazy with the brake pedal, I think if you don't hold it down long enough when you press the start button it won't start properly but I don't know. It hasn't happened nearly enough that I could possibly bring it to the dealership about it as there is hardly any chance it will happen when they're watching.