2005 Chrysler 300C engine problems
 

HI I have a chrysler 300c that i just sold that now has engine problems and im trying to help the person out but he wont tell me what hes done to the car, anyways the symptons are the cars kinda missfiring and when the car is idling the rpms keep going up and down like its wanting to shut off but struggling to stay start and then it finally chokes out and turns off, sorta like the engines not holding compression its kinda strange.

so i was wondering is someone could offer there expertise and kinda give us an idea what to do next or any kinda suggestions or help tips would be appreciated cheers

can only offer a tip take it to a shop to have them look at the codes or anything else

If there's an idle problem, it sounds like a problem with a vacuum hose
If it's misfiring, it could be a problem with the plugs or wires
Just remember, according to the manual, it says you can use 87 octane, but recommends 89 for best performance
Does it throw any CEL codes?

However, if he's done some engine modification, technically you shouldn't be responsible for something he's done