Problem solved. Answers here: The hesitation at wot is NOT in relationship with the cold start issue. I have fixed the cold start issue. There was water in fuel. This water was caught in the fuel pump basket and froze sometimes, making difficult or impossible to suck gas and deliver proper flow. Flo...

Updates I have made several tests during the past week. I was able to use a scantool to see live data while the (no-start) problem occurs. When the engine doesn’t start, all the engine sensor signals are going to the ECM. While cranking, the crank sensor is around 275 RPM so I guess both P0335 and P...

Today, -3deg. The car did not start. No DTC. Tried to start it for 15 minutes. It sometimes almost started. The engine was getting a little bit warmer each time. Then, the engine started several times but died after 1 or 2 seconds. When giving some gas immediately after starting, the engine dies lik...

Jimmy57: Voltage drop is 0,31V I have tried another relay and get the same voltage drop. It looks normal. alschnertz: Coils, spark plugs and wires have been changed with good quality parts less than 10 000 km ago. They can be bad again but I doubt they are part of the problem. Misfire codes aren't p...

Thanks for your input alschnertz. I have worked on the car today. It really doesn't look like a fuel delivery problem. The problem is getting worst. It is sometimes difficult to restart the engine when it is hot. It skips a little bit while starting with engine hot. The ECM finally throws some codes...

Thanks for your answer jimmy. That makes me think my MAF is ok because when I test it while the engine is running, it gives me normal readings. I'll take a look at this update you are talking about. Now I have to do more investigation to find the problem. Any thoughts about what could be the problem...

Hi there, First , I’m a mechanic. My 2004 volvo v40 is hard to start when it’s cold outside (below 6 celcius). When I start it, the engine (almost) fires up and dies immediately. I try to start it several times and after 4 or 5 times, it starts. It doesn't help if I touch the gas pedal. When outside...