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Mike S.
Mike S., Mechanic
Category: Car
Satisfied Customers: 7568
Experience:  25+ years experience as an auto mechanic.
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Car keeps cutting off at different time, at stop or on the

Resolved Question:

Car keeps cutting off at different time, at stop or on the freeway, sometimes will start right up and will not, can you help me get a ideal of whay it could be?
Submitted: 7 years ago.
Category: Car
Expert:  Mike S. replied 7 years ago.
Most of the times a tune-up will fix most problems. Do a complete tune-up and change the fuel filter and check for codes. Tune-up should include spark plugs, wires, cap and rotor if equipped, air filter, fuel filter, pcv valve, breather filter if equipped, set the timing if adjustable, clean carb or throttle body, check vacuum hoses. Clean injectors if equipped.
Customer: replied 7 years ago.
Could the coil packs in the spark plug wiring cause the reactions?
Expert:  Mike S. replied 7 years ago.

Do a cylinder balance test and see if every cylinder is firing the same amount, listen for the cylinder when it dies, they should all be about the same, you could hook up a tach and watch the tach.


First of all you will need a 12-volt test light and about 8-12 inches of neoprene vacuum hose. The vacuum hose will conduct electricity cause it is carbon based, use an ohmmeter if you aren't sure and see if the vacuum hose you have will conduct.

Now, cut off the same # XXXXX cylinders you have in small equal lengths of the vacuum hose. 2-3 inches will do fine. The small diameter kind like to carburetors, etc will work as long as they fit over the distributor cap tower connection.

Now, mark all your spark plug wires at the cap or coil pack and remove them all. Put those short pieces of vacuum hose on the distributor cap or coil pack connections and shove the other end of the vacuum hose into the spark plug wire boot until it makes a good connection.

Now connect your 12 volt test ground clip to a ground and start the vehicle. With the engine running touch the 12 volt test light to each of the vacuum hose 1 at a time and listen for the cylinder to short out and die and drop in r.p.m. They should all be about equal. If 1 or a few don't drop or do anything than you have your dead cylinder there.

Customer: replied 7 years ago.
Is there anything I need to know about this situation that I didn't ask or that you can tell me or help me with?
Expert:  Mike S. replied 7 years ago.
Well yeah, you could tell me the year,make,model,engine. If the check engine or service engine soon light is on. Did this problem occur suddenly or gradually just get worse.
Customer: replied 7 years ago.
2004, kia optima, 2.4, its gradually gotten worse.
Expert:  Mike S. replied 7 years ago.
Then it could be the spark plugs or fuel filter. Start with either 1.
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