1993 Volvo 240 Cold Start Problem

'93 Volvo 240, 2.4L, 175,000. I've had this car for 3 winters and when the temp gets below 30 degrees, it starts very rough or not at all. It does not have a dedicated cold start injector like other models. I have replaced the coolant temp sensor, checked the ECU as per the Bently repair manual. No codes are stored in the computer. All injectors have been removed/tested and are in good shape. Seems as if it is getting plenty of gas by the smell of exhaust as it coughs and sputters during attempted start. Once it does start and accellerates above about 1000rpm, it runs fine. (as if a cold start injector had just cut out). Any ideas? Thanks