Can someone diagnose this?

[fa22_raptor]

Hey all. Recently, my sister's Mitsubishi Lancer's been having a very slight problem. When starting up, the engine struggles to start and vibrates rather violently. The RPMs are below idle for a few seconds, and you need to rev the car to get it to idle properly. She just changed the battery a few days ago to see if that was the problem, but it didn't help at all. It only happens upon ignition, and when just idling at the traffic lights or something, it's perfectly fine. It's a strange one... Does anyone have any ideas what it could be?

[johnnynumfiv]

Idle Air Control sensor, probably, could be a few other sensors, no check engine light?

[Matra et Alpine]

What engine, how old.

If we're assuming injection then juhnnynumfiv is most likely.

If not ( or in some case single point injection ) then it may be a leak in the inlet manifold. If you use the throttle can you hold the engine steady at idle speed ?
If yes, then unlikely it's a leak as it generally drops revs.

[pimento]

If it's a carburetted one, clean the carbie.

[targa]

Hey all. Recently, my sister's Mitsubishi Lancer's been having a very slight problem. When starting up, the engine struggles to start and vibrates rather violently. The RPMs are below idle for a few seconds, and you need to rev the car to get it to idle properly. She just changed the battery a few days ago to see if that was the problem, but it didn't help at all. It only happens upon ignition, and when just idling at the traffic lights or something, it's perfectly fine. It's a strange one... Does anyone have any ideas what it could be?

i have been having the same problem, without the violent vibration, it will kick up to an amazing 250-300rpms and bounce a little, then it will kick up to idle speed and be fine....idk what it is....but it sucks

[ruim20]

Electronics maybe?

[Quiggs]

Might be a dirty throttle body. Is the car throwing any CEL codes?

[Egg Nog]

If the engine struggles to start at first, there's a good chance that you might just need a new fuel filter. Has it ever been changed?

[targa]

If the engine struggles to start at first, there's a good chance that you might just need a new fuel filter. Has it ever been changed?

not mine...car just turned 40,000 miles yesterday...didnt think it needed a change that early

[Egg Nog]

not mine...car just turned 40,000 miles yesterday...didnt think it needed a change that early

Most car companies recommend that you change the fuel filter every 30,000 miles (50,000km) or so. I've talked to a couple mechanics said that doing it twice as often will definitely extend the life of the car.

[targa]

Most car companies recommend that you change the fuel filter every 30,000 miles (50,000km) or so. I've talked to a couple mechanics said that doing it twice as often will definitely extend the life of the car.

guess i need to get to doing that then

[Waatz]

Mitsy's have a very common fault with the ISC (idle speed controler) or stepper motor, they have a series of coils inside that have power applied at verious times to open and close the idle valve, sometimes (very often) these coils or one in particular will burn out due to it being powered more than it should be, the car will run fine until the battery is disconnected (which looses the ECU's memory)
A new ISC motor normaly costs about $300NZ + fitting and setting up.

[aussie italian]

mabey beceause its a mitsubishi


(jks)