vibration

1989 DAIHATSU CHARADE
50,000 MILES • 1.3L • 4 CYL • 2WD • AUTOMATIC
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HKHKHK
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  • 2 POSTS
Vehicle starts easily, idles smoothly in "park" or "neutral", and runs smoothly when accelerating and at highway speeds. However, after shifting initially into "drive", there is noticeable vibration felt in the steering wheel. Applying the brake adds additional vibration, as does turning on the headlights or placing additional load on the electrical system.

Motor mounts are in good condition, neither loose nor broken.
I replaced the spark plugs yesterday with the recommended NGK model, however the others, Champions, were clean and installed less than one hundred miles ago. No difference in performance noticed subsequent to the change out. Also, I could not detect a vacuum leak.

Vibration has slowly increased during the last few months. As a consequence, I have been shifting into "neutral" just prior to approaching a stoplight or stop sign, to avoid the vibration.
Jul 27, 2016 at 11:31 AM
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FREEMBA
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  • 1,152 POSTS
Check the engine for vacuum leaks. Check all vacuum hose (including the brake booster hose). Check for vacuum leaks around the throttle body gasket and intake manifold gaskets.
Most shops will "smoke test" the intake system for leaks. This is the best way, but can be expensive so call a couple of shops and compare prices.
Another way (though less accurate) is to spray small amounts of water around the suspected leak area or hose. If there is indeed a vacuum leak there, it will draw in the water, thereby causing the engine to stumble/sputter, identifying the area of the vacuum leak.
Another method uses carburetor cleaner instead of water, but presents a fire hazard and is not recommended.
Jul 27, 2016 at 8:31 PM