2002 Mazda 626 Car shakes when stopped in drive, neutral or park.
Original Post: 2002 Mazda 626 4 cyl with 85000 miles
I have a 2002 Mazda 626 4 cyl with 85,000 miles. It has a bad vibration when idling, Once the car starts driving the vibration is no longer noticeable. My car idle is set about 650 RPM at a stop in gear. If I rev my engine to about 1000 RPM the vibration smooths out. When at a stop I notice that using the AC or turning the steering wheel seems to add to the load and the RPM fluctuates sometimes to the point where I think the car will stall. The plugs, wires, firing coils and distributor are new (replaced 2 months before this problem started) all the motor mounts are new, new brakes, belts, tires and 4 wheel alignment. New air filter, oil and filter and the transmission fluid is full. The vibration actually got worse after I replaced the motor mounts. Any ideas? I cannot find any loose or bad vacuum hoses... one hint... the vibration started when I had the air filter replaced. It would idle rough when I was in drive with the brake on but in neutral or park the vibration would cease. After replacing the motor mounts (3 were busted, replaced all 5) then the vibration became worse and is present in all modes (park, neutral or in gear). Could something have clogged the Mass Air Flow valve when the tech replaced my air filter? By the way... the "check engine" light is not on.
Turns out the issue was a bad Harmonic Balancer. When I first heard the news I thought, okay those are a cheap part and cheap fix, well... you realy need to buy the full kit that includes the serpentine belt and tensioners. Best price I found was about $160. The repair shop quoted $183 so I let him buy the part so I could get the part warranted by the repair shop. If your car is older like mine (just reaching 100,000 miles) and you have not replaced your timing belt and water pump I suggest doing all 3 of these at once. A reputable service shop will not screw you on the labor. They also pointed out that all my hoses are original and are showing signs of age cracks so I am having them do that as well. At Lambs Automotive here in Austin I am looking at $1100 for everything mentioned including an oil change and State Inspection which is due in January. All this added to the other repairs conducted in the last 2 years my 14 year old car should be good for another 100,00 miles.