Mechanics

CHECK ENGINE LIGHT

2006 Mitsubishi Lancer Evolution • 45,000 miles

Was random misfire but was fine so I had it cleared. Then a few days later I got a really bad vibration in the engine and a loss of power. Any ideas? The vibration is constant but gets much worse when the turbo spools. Sluggish exhaust noise as well.
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Colin333
January 22, 2012.




There are a few things that can cause this problem;

You may have a bad compressor seal causing a lean mixture issue casuing the misfire.
The MAF may be bad.
There could be other vacuum leaks.
You could have a faulty injector.

The first thiing that is the easiest to try is to dis-connect the MAF and see if it runs better. If it does then the MAF is at fault. You can clean it with MAF cleaner, but the sensor wires are so frail on some sensors you may not be able to do it. Otherwise you will have to replace the MAF and that is expensive, so you don't have anything to lose. I have heard of people using isopropyl alcohol to clean the sensor wires off.
You may just have some common problems that cause misfires like a vacuum leak elsewhere.
I am giving you a link to a diagnostic walk through if the MAF test does not work. To check for a bad compressor seal, you should be able to hear it sucking in air with the hood open and listening closley to the turbo. Also, visually inspect it for sign of leakage as it may puch out some stuff when the blow-off valve opens.

Here is the link;

http://www.2carpros.com/articles/engine-misfires-or-runs-rough

Let me know if you need anything else and I will get back to you ASAP.
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Would a misfire cause the vibration?

Tiny
Colin333
Jan 22, 2012.
The engine misfire would make it vibrate at certain RPMs especially near its resonant frequency.
The other thing that may be wrong, especially with a transverse mounted motor and all that horepower, are the engine mounts. They go bad pretty quick especially if you drive the car hard. You can check this by starting the car and putting the parking brake on. Open the hood so you can see the engine as you are going to watch for excessive movement, more than a few inches of travel at the most. Should be very little and return to postition quickly. Then, put in first and give it a little bit of quick gas and clutch while watching the motor. If it moves as though it had nothing to damp or control the motion from torque and/or it moves more than an inch or so, the motor mounts are probably shot. The thing about replacing mounts is that the front one fails first in most cases. Some people replace just the front and the other mounts like the back mount are near failing and the load is transfered to the new front mount and it gets detroyed. So, you have to replace the motor mounts as a set and it is a good idea to replace the transmssion mount as well. If you want to get some longer lasting mounts or strengthen a stock set to prevent or at least lengthen the time it will take before they fail, you can get polyeurethane mounts or inserts. The mounts are sold in sets and will keep the engnine form moving around better than stock meaning better power transfer. The 2 places I would suggest getting mounts are innovativemounts. Com or hasport. Com. They will last the life of your car. Get the standard shore grade as anything else will be too rough. The other option is to get a set of new stock mounts, or you may be able to salvage your old mounts depending on how bad they are, and buy some inserts from Energysuspension. Com. They will have a full kit for all mounts for much less than getting the hasport or innovative mounts. They will be a little harder than stock but still retain some of the vibration isolating qualities that stock mounts have.
So, get the misfire straightened out and then if it still vibrates check the motor mounts.


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