I have a 2005 A4 1.8T. Recently the engine is rough starting when cold. When the dash temp shows +3 degrees or higher, the engine starts at 1200 rpm and drops to 800 rpm after 2 mins.

When the dash temp shows less than +3 degrees, the engine starts rough at 800 rpm, and then idles more smoothly after 2 or 3 mins.

This seems opposite to what should happen. It should start at the higher rev when colder, not warmer. I had this car since 2005 and it always started at 1200rpm and drop to 800 rpm after 2 miins when cold (in Summer and Winter).

Did anyone have a similar experience and know what the fix for this would be ??

 

Did you get it scanned?
I had some odd rpm readings myself at cold start. After a couple of months of that the car just refused to start (last Thursday). I had it towed to my mechanic as soon as the car was off the flat bed truck it started at first try (you can imagine my frustration after just forking $110 to have it brought there). The mechanic scanned the car and told me that the cold affected one of the sensors detecting the engine moving when attempting to start it and that probably the 10 deg change in temp in a couple of hours affected it. I ended up replacing the sensor and I am a happy camper now .

 

Can't help you on the roughness but mine does the same thing when its around 3C it idles around 1200 then drops to 800 and when its really cold like -25C it starts and idles at 800 and stays there, 02 1.8t. I'd check your spark plugs out.

 

Do you know which sensor was changed ?? This motor seems to have too much electronics / control modules !!!

 

Hi seanf, Did you try anything to correct the situation ?? Your engine is doing the same as mine. Low rpm when colder....high rpm when warmer (weird).

 

Honestly I think its normal, I never thought anything about it, but when you say roughness I'd have a look at your spark plugs if they have not been changed in a while that could be the cause of your rough starts.