Paul Messam, Gleaner Writer

Are you able to spot when there is missing, surging and lack of power in your car? Surging describes an engine that delivers a pronounced variation in power the accelerator pedal and the throttle are kept steady. To the driver, it seems as if the car is speeding up and slowing down.

Missing occurs under two operating conditions - idling and underway. An engine that misses when idling, runs unevenly and feels as if it is skipping. If the condition is bad enough, the car shakes," confirms auto mechanic Hopeton Forrest. A missing engine gives a steady pulsating or a jerk that usually becomes more pronounced as load on the engine is increased. The sensation is not normally felt at 50 kph. A missing engine often causes the exhaust to produce a steady, spitting sound.

sluggish action

Lack of power does not necessarily mean no power, it means a sluggish action. It occurs when an engine is not delivering the power it should at high speed or when put under load. According to Forrest, the car does not accelerate to the speed it should , it loses speed going uphill, and it has less-than-normal top speed for the position of the throttle. The factors that cause stalling can also cause missing. Here are some checks to track down the real cause:

Checking on power loss

Check 1: Check for vacuum loss through loose or split vacuum hoses.

Check 2: Ensure that no leak exists.

Check 3: Examine carefully the primary ignition wires at the coil and the distributor. Replace the wires that have cracked insulation, and see that the wires are tightly connected.

Check 4: Disconnect the carburettor air vacuum tube if one exists. Plug the tube opening or the opening in the air cleaner or manifold so vacuum is not lost.

Check 5: Disconnect vacuum hose of the exhaust gas recirculation (EGR) valve. Plug end of the hose so vacuum is retained while the engine is running, make use of insulated pliers to avoid a shock. There should be a drop in the engine revolution per minute (rpm) as each plug is disconnected.

If there is a drop in rpm, check the following:

1. Thermostat air cleaner.

2. Distributor and distributor points.

3. Engine timing and carburettor mixture and idling speed.

4. Positive crankcase ventilation (PCV).

5. Remove the spark plugs. Examine for cracks, wear, improper gap, burning or fouling. If missing continues, test each spark plug cable.