Plugs At what mileage should the spark plugs be replaced?

There isnt really a mention on how often you should change your spark plugs some manufacturers say certain plugs are good for upto a certain mileage
Check with your spark plug manufacturers recommendation on spark plug changing intervals

https://www.ngksparkplugs.com/about-ngk/faqs/spark-plug-faqs/how-often-should-i-replace-my-spark-plugs

remember your going to a mechanic shop $$$$ that's why / next go to 2007kia Sorrento owners manual and download it the mileage maintenance recommendations are in there

A lot of things can cause a car to burn more gas. A clogged fuel filter, bad spark plugs and spark plug wires. Also a clogged O2 sensor will cause the engine to work harder reducing fuel mileage. Perform a complete tune up, replace the spark plugs and wires, replace the fuel filter and air filter.

Take the vehicle to an auto parts store and have them read the computer faults Is the yellow check engine light on ? If you are lucky replace air filter, replace spark plugs that might help. If it is a high mileage vehicle it's likely to be an oxygen sensor, or the converter might be plugged up. If either or both of these are present the computer will stop managing (reducing) fuel flow and go to open loop and all that fuel gushing thru the engine will ruin your gas mileage and spark plugs !

replace the spark plugs with high out put spark plugs and and put a high air flow filter on it.

hello Fuel Type Regular MPG (city) 25 MPG (highway) 34 MPG (combined) 28

Poor gas mileage can have many roots but the best way is always to start with the ignition system. Have a look at the sparkplugs, if you've got the I6 4.0 engine it is easy to check them. Spark plugs are cheap and easy to replace. Also check the spark plug wires, be sure the connections are tight and free from rust. Check the distributor cap and rotor and if they are rusty/greasy clean them up. After you've cleaned and checked the ignition items (spark plugs, wires, distributor cap and rotor) you can move on to the fuel injection system.
Replace the air filter, it is cheap and most people overlook that single item.

When was the last time you replaced the fuel filter? A clogged fuel filter reduces power drastically which in turn affects fuel mileage.

i recommend to replace the spark plugs and the spark plug wires (it is always recommended to replace both at the same time) it is also a good idea to replace the air filter and fuel filter if this hasnt been done long time or if you do a lot of driving and you have done it in a while i still recommend to do so and it is a good idea at this time of the year to change the oil if it hasnt been done w/i the last 3 months or 3,000 miles which ever is first. this will fix that spark problem and improve gas mileage.

AC 41803 Drivetrain:Four Wheel Drive;
@Gap .045" This is a Platinum High Performance Spark PLug


Option : ASP AR25
EngineVIN:W;
@Gap .045"@ High Performance

Stay away from those Gimmick Spark Plugs , they are just more money for nothing. A good platinum spark plug is all you need, the key is to gap it correctly to your application...

On GM products Vin # W it is .045 plug gap
On Gm products Vin # Z it is .035 plug gap

You will not have huge gains in fuel mileage from replacing spark plugs except to say that if your old ones are just extremely bad, there is no magical spark plug with extra mileage manufactured into it.... Hope this helps...