okay first of all i would like to start by saying i've had this issue with my car ever since i got it. it was my first car & its still my first & only car so far.

but anyways since i got it ive always had an issue of starting it. i can start it like nothing when the engine is cool, like when im heading out in the morning. but after ive had it on for a while & i get to my destination if i want to turn it back on i have to try to start it at least 2 or 3 times! sometimes it wont even stay on because the rmps will be super low & it will eventually turn off. & what i do sometimes is step on the gas but as soon as i take my foot off the gas the car turns off again! there is definitely something wrong with my rpms because another issue i have is that my rpms are never neutral or where they are supposed to be in idle. they are either too high or too low. maybe that has to do with my car not starting but ive taken my car to shops & they can never find the a fix for it. & some just say that they dont work on mercedes & i dont want to take it to a dealership because that would be a lot of money! anyways maybe someone can help me out with this. i dont know much about engines but ive fixed several things in my car with diy guides anyways if anyone could help it would be great!

-thanks in advanced