Can u help me fix my car

Hope this helps 4d56

95% sure its your heat shield over your muffler, other causes could be, shocks or struts, exhaust system or muffler loose.

This is called surging, and can have a number of causes.
1. There's a leak/crack in a vacuum hose. Check and replace as needed.
2. The throttle body IAC motor is jammed or busted. Usual cause is a build up of carbon and oil sludge in the throttle body (TB). The fix is to pull the TB off and thoroughly clean it. The build up can also indicate high oil use.

For a 10 yo car, its probably done around 150,000km, and the valve guides and seals are worn. Do a compression test. Follow the car and see if it blows blue or black smoke on acceleration. Worn guides may also cause the engine to fail an emissions test. The fix, if you are so inclined, is to pull the head, get it overhauled and put it back on.
You may decide that this car is not worth buying.

Your head gasket has failed. Check your oil to see if it's a milky white color, which indicates that the coolant is leaking into one or more engine cylinders.
This problem should be fixed ASAP, it will cause major engine damage.

Manuals are available to be downloaded with a cost so log On;

www.buyrepairmanuals.com/mitsubishi/lancer

This might help
www.diyautomanuals.com/repair-manuals/Mitsubishi-Lancer-Repair-Manual.html

why fix something thats not broke sounds like everythings alright

check your plug wires I had same problem, turned out to be a bad wire.

go to a junk yard or see if their is an after market lens cause the dealer is so expensive i seen several at the junk yard i went to toaday in utah

same as mine
2000 Lancer cedia

change the oil pan gasket