BIG HELP NEEDED For Volvo 440 SE

first thing i would do is make sure the multiplugs behind the dash are correctly and solidly inserted - i had a similar problem on my first 340 - turned out it was because one of the multiplugs had fallen out

Still Need Help 

Hi, just a possible. When you went to the agent did you ask for the engine temp sensor or the temp gauge sensor? They are 2 completely different items. The engine temp sensor is linked to the fuel system to replace the old choke style system. The temp sensor activates the gauge. this may well be the problem. Someone correct me if i am wrong but doesnt the 400 temp sensor locate on the front of the cylinder head? regards, Keith