I have a 1983 volvo 245 turbo wagon I purchased a couple months back. At the time the car started fine and ran great. I did a basic tune-up (plugs, wires, cap/rotor, fuel filter, and air filter) as it has 183000 miles and who knows when the last maintenance was done. At any rate, lately when I start the car it fires up fine, but dies immediately after a sec or two. It will continue to do this unless I push on the accelerator and hold it at 2500-3000 RPMs for 15-30 sec. After that it will idle fine. Note, I live in Idaho and the temperature is starting to cool off. According to my Haynes there is a coolant sensor that controls a cold start injector?? Before I rip and tear, I thought I'd see if anyone else has had this issue and what they found as the cause. One other wierd thing is that there is a loud clunk under the passenger floor when I shift gears and the engine is cold. Any help is appreciated. Thanks!

Russ