Question about Buick Cars & Trucks
The basics for vehicle with rough idle, check for a leak of some kind, fuel--egr--vacuum leak. How long since an over-all tune-up? You can check the idle air system? Any applicable trouble codes? To check codes yourself, at the least, you need an obd2 code reader.
If spark issue, sometimes you can use a digital multimeter to do some testing, low tech, non--invasive. With digital multimeter on low voltage setting, engine idling, touch spark plug wires, one at a time, do not penetrate insulation, don't take spark plug wire loose, it's an inductive reading. The point is if you get a reading bouncing off zero, that is where you start testing. I know you changed the coil/s, but sometimes, you need to check ignition module. I'm not saying that module is faulty, I don't know.
Posted on Feb 25, 2017
This can be your Idle control valve, when you turn the air on it puts the engine under load and your computer will increase the idle automatically to prevent the engine from cutting out.
When you are standing still and the car is shaking, by touching the accelerator very softly does the shaking stop? If so check the idle control valve.
I hope this will help.
Posted on May 13, 2009
I just had this fixed on my suby today. The cause is that the spark plugs, go through the valve covers on the 2.5 l .When the o rings in the cover go, the result is oil in the spark plugs. The cost of the repair in Canada was about $500 including diagnostics as well as new plugs and wires About 1.5 hours labor and new seals and gaskets. It now runs like new. This is a common problem for this subaru engine as well as for the dodge neon.
Posted on May 23, 2009
The problem is a faulty solenoid in the vapor recovery system. The solenoid is sticking open and allowing fumes from expansion of fuel in the fuel tank to enter the air intake and smother the engine. This is how the Mazda service tech explained it to me. It is a known problem on the Mazda 3 in various trims which Mazda refuses to acknowledge. Usually the check engine light comes on and the engine diag code reads mass airflow sensor, which is incorrect. I dealt with this for 6 months on my wife's 2005 Mazda 3i before the dealership figured it out. My cousin bought a 2007 Mazda Speed 3 which developed the same problem after a few months and was cured by the same fix.
Posted on Aug 26, 2009
Perform a valve clearance inspection and adjust if necessary. Tight or sticking valves will cause a misfire or rough running concern. Note: Perform valve adjustment when the engine is stone cold. 4cyl: INT 0.26mm EXH: 0.30mm (V6 engine are hydraulic and no adjust necessary.) Also check for a sticking or stuck open EGR valve. For diagnostic purposes only: Remove the EGR valve. Place a business card over the EGR passage and bolt the EGR valve back on. This plugs the EGR ports and if the misfire goes away the EGR valve is partially stuck open and is defective.
Check for low fuel pressure. Check for low compression. Check cam timing. Check for a weak ignition coil. Also don't over look the possibility of worn or broken engine mounts which cause excessive engine movement and engine vibration. -hope this helps
Posted on Mar 05, 2010
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