Hey! Having some issues with my Ford C-Max (2007) and wanted to ask if anyone’s had something similar happen.

So the car starts having trouble when I shift into first and give it a bit of gas - if I give it too little gas it just dies. Now it’s started doing the same thing in second gear too. When I first start the car and let it idle, the RPM drops every 10-15 seconds or so (from about 900), but it gets better after running for a while.

Got the yearly checkup recently and everything was fine, but then this started happening. Also got a check engine light that keeps going on and off every other day. It’s pretty cold here, like 5 degrees if that matters.

I’m going to take it to a mechanic when I have time but wanted to ask here first if anyone knows what it might be? Maybe the MAF sensor or something with the idle control?

Thanks!​​​​​​​​​​​​​​​​

    • skip0110@lemm.eeEnglish
      1·
      5 hours ago

      I was going to say vacuum leak too. Get some brake kleen or other flammable liquid and spray judiciously near different parts of the intake while the engine is running and listen for a change in idle to help locate it.

      Note: spray flammable liquids at your own risk. If you don’t know the risks and what to avoid have a mechanic do it.

    • sturlabragason@lemmy.worldOP
      1·
      6 hours ago

      Thanks all, already went by my mechanic once to get the codes, but no engine light or error was present just as i started it then 🥲

      Will try again next time I ger the light.

  • jubilationtcornponeEnglish
    2·
    7 hours ago

    Lots of things that could cause rough idle. Vacuum leaks and spark plugs are common culprits. Dirty/worn spark plugs are often accompanied by unburned fuel or soot in the exhaust.

    You’d have to put a vacuum gauge on the intake manifold to check for a vacuum leak.

    Beyond that, you’d have to check the diagnostic codes to see if it shows something else amiss.

  • GrumpyDucklingEnglish
    4·
    11 hours ago

    There’s a few c-max forums you can check. Pulling codes would be helpful. There’s a program called forscan for fords that will give you a lot more information than a basic scan tool. I saw a few threads where people had the same issue but no resolution. Just don’t fire the parts cannon at it like one guy did. There’s lots of things it could be. You might just do a quick visual check to see if anything looks off. Make sure the airbox lid and hose are on correctly and tight. Check the vacuum hoses and look at the throttle body connector. It has an electronic throttle, so the pedal couldbe messed up somehow too.