2008 Fusion won't start in very cold weather

Thanks for answering so quickly. Do you spray where the air filter is? If it's a dying fuel pump, would we not have problems all the time and not just in very cold weather? The car runs perfectly fine otherwise.

I'll try that tomorrow. Going to be extremely cold tonight, so.....Didn't know that about the fuel pump. Good to know. Thanks for your help.

Just an update on the 2008 Fusion. The temperature here has been cold. Car now starts and then dies right away, almost immediately. It continues to do that. Check engine light is on again. Does the fact that it starts and then dies right away indicate that it might be the fuel pump relay? I brought this up with the mechanic and he said that the code reads an internal problem and he doesn't think that it is a fuel pump/relay problem. He now thinks that the pcm has to be replaced. He figures that it is not sending enough voltage to start in cold weather. The pcm was reprogrammed to the latest calibration and codes were reset at Ford dealer and all was fine until it got cold again. Hence, the problem above. Hit the bottom center of the gas tank to but nothing changed. When the pcm was reprogrammed at the dealer, should there not have been an indication that there was a problem with it? From what I've read, this is a $2,000 part and who knows if it will this fix the problem. If it does turn out that the pcm is the problem, then was replacing the throttle body necessary? The car had been running fine until a month ago. Thanks for any help you can provide.

It hasn't properly started, so we haven't brought it back to the mechanic yet, so I don't know the trouble code. It is supposed to warm up a little this week, so hoping we can get it to him soon and find out the code. No, it won't continue to run if we step on the gas pedal. We've even started it with the pedal down a bit, but it makes no difference. I had also heard that starting it in neutral might help, but that did nothing. Just wondering, is there a unique code for a pcm problem or would there likely be several codes?

Luckily (or maybe not so luckily given what's happened lately), the mechanic is a friend/acquaintance, so he won't charge for the diagnoses. Certainly, if I had to bring it to Ford every time, I would likely buy one. I'm going to just have to wait until it warms up enough for it to start so I can get it back to him to have it read. Thanks again for all of your help.

Hi would like to offer another possibility. It may not apply in this instance, but thought it worth mentioning. Had this exact same problem previously with son’s 2006 ford Explorer, 4.0 SOHC engine. Tried many different approaches to solving problem, then stumbled across a Ford Explorer owners forum where they talked about replacing O-ring gaskets on Intake Manifold. I bought the kit at local auto parts store for about $45.00 I think, and spent 2-3 hours taking it all apart and putting it back together. It started on first turn of the key and has never failed to start again in our tough Boston area winters the last 4 years. The explanation for this is that over time the O-rings dry out and shrink a bit. They still maintain enough vacuum to start when it’s warm out, but once it got cold and O-rings contracted a bit, it never would start. When I took out old O-rings and compared to the new ones, they were half the thickness. So, as I say, it might not be the same situation with the engines in the Fusion, but the description of the problem, and lack of other solutions working sounds identical!!

We ended up replacing computer and selling the car. It seems like the computer replacement was ultimately the answer. Expensive venture.

Thank you for posting this. I've had the exact same problem with my 2008 Ford Fusion the past two weeks. Same symptoms. I read a thread in another cartalk forum and they resolved the problem by replacing the MAS (or MAF) sensor. To test the car unplug the MAS/MAF sensor when the car won't start and if it starts up then the MAS/MAF is bad or dirty. Yesterday morning my car wouldn't start again so I unplugged the MAS sensor and it started right up. I bought some CRC MAF cleaner after work and followed a step by step video on YouTube. No problems this morning but the temperature was around 35 degrees. Hopefully the cleaning works or I'll have to replace the sensor ($115 from the dealer). Car runs good otherwise... needs to last me another 2 years if possible.

I hope that continues to work for you. I ended up replacing the computer, which in my case, seemed to be the problem.