Would A 2006 Chevy Equinox with just 40,000 miles

First check the fuel filter. And for best results check or tune up your system.
Engine Tune-up Checklist When you bring your vehicle into Firestone Complete Auto Care for a tune-up, you are essentially asking our skilled technicians to inspect your engine, analyze vehicle performance, and make adjustments as needed. The engine tune-up checklist will include both preventative and restorative engine assessment, and final maintenance recommendations that will vary from vehicle to vehicle based on age, mileage and unique manufacturer recommendations.
To give you a better idea of what happens under the hood when you drop your car off, we've compiled a basic engine tune-up checklist:

1. Check visual appearance of spark plugs: are they worn? What color are the insulator firing noses? An engine in good condition should have spark plugs with light tan or gray insulator firing noses. Any other color could be the sign of an engine problem.
2. Test the performance of spark plugs. What color is the spark? Is the spark properly igniting the fuel?
3. Check spark plug wires to make sure they are not hard or cracked.
4. Check the fuel filter to make sure it isn't clogged or dirty.
5. Check the engine's fuel pump for proper function.
6. Inspect the engine's fuel injectors to make sure dirt or other deposits are not restricting the amount of fuel that can be delivered to the engine.
7. Make sure fuel injector buildup isn't affecting how the spark plugs fire.
8. Adjust the engine timing and idle if necessary.
9. Check that the PCV valve isn't clogged or leaking.
10. Inspect the vehicle's points and condenser

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WOW! either you drive a lot of miles or you've been getting ripped-off. The orignal spark plugs are good for at least 100,000 miles. It's possible that you did have a faulty injector all-along and they didn't idenifiy the problem right away. If they have been installing the wrong [ cheap ] plugs then the plugs won't last long. Hope this isn't a Dealer, if it is, I'd call the GM 800 number and complain.

Modern spark ;ugs can easily go 50,000 miles. If you think you need new plugs, go ahead and change them out. It certainly wouldn't hurt, and it might give your horsepower and fuel mileage a little boost. I would recommend using Iridium spark plugs from either NGK or Autolite. Personally, I use E3 spark plugs. They did wonders for my old '96 4.3 GM V--6. I would also invest in a premium set of spark plug wires, Don't scrimp on the wires, they are a vital link in the ignition system. A cheap set of plug wires can cause multiple misfires which would play havoc with the on board computer.

Replace your spark plugs and spark wires.
Check you tire alignment and engine oil levels and replace your fuel filter.
Check your transmission fluid and coolant levels and brake fluid levels.
Cabin air filter replacement is also recommended.
Check your battery output voltage and see if an recharging is required.

i think this just a idea but i wonder if a clogged fuel filter and its lurching cause getting little gas and plugs black cause burning themselves too little fuel hope this helps

oil/filter/lube every 3,500 miles synthetic oils every 5,000 miles
tire rotation wheel align check balance every 7500 miles
transmission service every 30,000 miles
air filter gas filter cabin air filter evry 30,000 miles
if engine has a timing belt(rubber substance) replace every 60,000 miles if it has a metal timing chain lasts almost forever
spark plugs should be good for 75,000-100,000 miles before replacing
Spark plug wires every 50,000-60,000 miles approx.
fuel injector flush every 30-40,000 miles approx.

Not brakes. Check for something stuck in the tire.
or something loose in the hub cap.

no i don't think so

You need to go to a dealer or a certified mechanic. If you don't know already. Usually these will be the things you have to purchase, plugs, wires, air filter, fuel filter, oil filter & oil, you will need to flush the radiator and the transmission.

Tune Time.
1)new spark plugs properly gapped.
2)new air filter (check every 35000 miles)
3)new fuel filter (every 35000 miles)
4)1 bottle of STP fuel treatment (red bottle) 4x a year.
5) oil and filter change (castrol or another good quality oil every 3-4000 miles.
6)proper air pressure in tires (check every 2 months
7) service transmission every 40000 miles or less.

New oil and filter
8) new plug wires every 80000 miles.