I would like to get some better gas mileage out my stock 99 yukon 5.7L Lets put a limit of $500 on it. suggestions include smaller diam pulley kit, cold air intake,electric compressor fan,different re-usable air filter kit. What really works? how about those aftermarket computer chips? Im looking at highway mileage as we do alot of highway driving.
Do a good tune up with new AC Delco Rapid-fire or Platinum plugs (whichever you have) replace the plug wires/cap/rotor as required, do an oil/filter change and use a good oil (Synthetic/crude your choice), Lube all fittings and check/change the rear gear lube, transfer case lube, and trans fluid. Change the air filter (use a quality filter like Wix or Baldwin) Check all belts and hoses for wear/damage. Check the clutch on the fan to make sure it is operating properly. Check the tires for wear and damage and air pressure. Make sure the brakes are in good shape and the parking brake is releasing fully.
Then just use good driving skills to lessen the amount of starting/stopping. The 5.7 has never been a high MPG engine, usual range runs from 9 - 18 MPG depending on the vehicle and it's wind resistance and the driver. The Yukon is NOT a good vehicle for mileage since that is not what it was built for anyway. Sorry but that's the facts.
As for the gimmicks and crap that claim to increase mileage they should be sold right next to tickets for the Cardiff Giant....
All of what Steve said is good concrete advise. One thing that I might add is have a 4 wheel alignment done to the truck. Talk to the alignment technician and ask him about the least amount of toe in that he thinks you can get by with and still drive safely. Two things this will do for you, one the tires will last longer and two less rolling resistance.
Interesting observations--thanks, I am just curious about improving mileage--I've overheard others debating the subject. I knew when I bought this truck that the mileage would be lousy, but the way I look at it is the truck is just an added insurance policy when involved in a accident and used for a couple times a year of hunting and off roading.. Thanks again for the advice--I will not be buying any of those things mentioned originally
I would recommend a Jacobs high energy ignition system with Mileage Master. I have it installed on an 88 K1500 ext. cab, long bed with the 5.7L. I can get 20mpg on the highway. I also have a good free flow exhaust system and a K&N filter.
Why do you think I'll blow the engine? It runs great and has 118k. If I remember correctly, one of the claims of the Jacobs ignition was to prolong engine life.
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