2002 LeSabre rough idle

[shinnox]

(posted this once and it was removed?)

I have a 2002 Buick LeSabre custom im having issues with.

engine rocking back and forth very hard. The car barely wanted to start and at idle the motor vibrates so hard it looks like its going to bounce up out there. Also had a prob with the breaks not wanting to work (pedal doesnt wanna to down?) right when this happened.

Icode reader it gave
P0300 multiple cylinder misfire detected
And
P0449 evap solenoid control circuit malfunction.

I changed all plugs, wires and coils. Didn't fix it. Tested the icm and it was fine. Replaced the EVAP purge valve. And still have the same issue.

Any ideas as to what it could be?

 

[jotzgr]

P0449 is the Evap Solenoid at the back of the car on the frame rail near the LR wheel. If it is not working correctly, you will have a huge vacuum leak which can create multiple misfires as well as the other problems you are experiencing. The code is leading you right to this. This is not the Evap Purge Valve on top of the intake in the engine compartment.

Symptoms of P0449 Buick​

1. Check engine light illuminated on the dashboard
2. Fuel smell near the vehicle
3. Rough idling or stalling
4. Decreased fuel efficiency
5. Difficulty starting the engine