FOUR MOST PROMINENT SIGNS OF TUNE-UP TROUBLE ~

You expect your automobile to perform properly under all conditions and usually it will, providing the many parts involved are in tune and working together as a team.  There are several signs indicating a vehicle is losing power and efficiency, and if overlooked will cause poor gas mileage, but wasted dollars.

POOR GAS MILEAGE

Are you stopping for gas more frequently, but actually driving less?  This could mean the gas going into your engine is not being used properly and wasted fuel is going out the tail pipe.  And at today’s dollars who can afford that?

In most cases a minor adjustment and/or tune-up is necessary to correct this problem.  A minor tune-up usually consists of inspection and/or replacement of:

1)     Knock Sensor

2)     Map Sensor

3)     Distributor Rotor if any

4)     Distributor Cap if any

5)     Spark Plugs

6)     Wires

7)     Loose connections or oxidation

Other factors contributing to poor gas mileage are:

1)     Poor driving habits hard acceleration through the speed limit and beyond.

2)     Low tire pressure increases grount0to-tire resistance.

3)     Incorrect wheel alignment – constant grount-to-tire resistance.

4)     Brakes dragging constant rotational resistance at all speeds.

ROUGH IDLE

Does your car shake like a bowl of jelly when pulling up to a stop,ight?  Sounds like rough idling.  This could be very costly if left unchecked and cause serious engine damage.

Conditions that will result in rough idle are:

1)     Defective or worn spark plugs

2)     Defective coil or spark plug wires

3)     Defective or worn ignition parts

4)     Worn valves, rings or leaky gaskets

5)     Malfunctioning EGR valve or EGR solenoid

6)     Malfunctioning NAP Sensor

STALLING

Does your vehicle start well then stalls, or come to a stop and the engine dies?

This indicates the engine is lacking something, perhaps fuel, ignition or air.  Many times it can be taken care of in minutes by a minor adjustment.  Conditions that results in stalling and can be fixed in a tune-up are:

1)     Ignition parts worn or defective (rotor, or distributor cap)

2)     Dirty air filter

3)     Excessive moisture on electrical parts

4)     Worn or defective spark plugs or wires

5)     Defective MAP Sensor or connections

6)     Malfunctioning IAC Valve

7)     Slosh of fuel through purge system

PINGING

Do you hear noises when driving up a hill or stepping down on the gas pedal suddenly?  Does it sound like a bunch of marbles in the engine?  What you are hearing is pinging.

The engine is being subjected to extreme stresses and if allowed to go unchecked, will result in serious engine damage.  Many times this condition can be corrected by using the proper recommended octane fuel for the automobile.  Pinging could also be caused by the following conditions:

1)     Incorrect ignition timing (PCM/ECM) Knock Sensor

2)     Incorrect fuel supply, (fuel filter, fuel pump, contamination) opening

3)     Incorrect PCV system operation

4)     Carbon deposits inside the engine

5)     Malfunctioning knock sensor

6)     Plugged EGR Valve

7)     Defective MAP sensor or connection

From Motor Age  November 2004     BECK/RNLEY