Home Travel Stories Gas Logs 1999 GMC Yukon 350 EFI MPG= 6.0 City
1999 GMC Yukon 350 EFI MPG= 6.0 City PDF Print E-mail
Written by Double Dragon
Wednesday, 28 November 2012 23:20

1999 GMC Yukon 350 EFI MPG= 6.0 City


Writing and photography copyright D. S. Brown


99 yukon gas gauge


EPA Estimate of Yukons when new MPG= 12 City/ 16 Hwy/ 14 Overall average.

The GMC Yukon has a 350 Cubic inch (5.7 L) engine hooked up to a 4 speed automatic transmission with overdrive. The Yukon 1500 averaged 1 MPG less with 11 City and 15 Hwy.

The door jamb sticker shown below indicates an approximate build date of Oct, 1998.

99 GMC yukon door jamb sticker

The final digits of the VIN are removed from the door jamb sticker shown below to protect owner privacy. The VIN 1GKEK13R7XJ decodes:

1= Manufactured in USA

G= General Motors

K= GMC Multi Purpose Vehicle

E= GVWR 6,001-7,000 pounds/ hydraulic brakes

K1= Full size truck/ 4 Wheel drive- 1500

3= 4 Door cab utility

R= L-31 5.7 L (350 ci) engine CPI

7= VIN check digit

X= 1999 Model year

J= Janesville, WI final assembly plant

Final sequence number not shown.

This Yukon SUV is not the modern equivalent of the old station wagons that were killed off by the profit margin possible to be made from SUV production. There was still a demand for station wagons and rear drive full size cars in the 1990s but the SUV craze and profitability of these vehicles prematurely wiped out station wagons and full size cars. Manufacturers needed that factory line to fill the insatiable need for SUVs.

SUVs are purportedly trucks. SUVs have high road clearance, 4 wheel drive, and oversize wheels with a tall square boxlike body. In the sense that is totally lacking in aesthetic style it is a utilitarian vehicle however for the purpose it is sold it is not.

Buyers want SUVs as a fashion statement while manufacturers pushed them initially as a way to provide a large vehicle that circumvents the CAFE fuel requirements for cars as well as enjoying lax emissions limits. Trucks are exempt from passenger car regulations and even though SUVs are just cars that look ugly they are technically 'trucks'.

This particular GMC Yukon has power leather seats, A/C, power windows, power steering, power brakes, power heated outside rear view mirrors among other luxury car features. It really has no resemblance inside to the old school 'get around truck' or off road vehicles. This Yukon has 3 rows of seats with a removable 3rd seat. If you have a big family or soccer practice mom duties it can carry plenty of people; but so can a station wagon.

The station wagon of the old days had the same seating room inside but was a car and hence incorporated the same stylish front end design as cars of the period as well as the dash and interior of a regular car. You didn't have to climb up into a station wagon because it wasn't artificially elevated for high clearance needed on off road duty that never occurs. Because the station wagon was long and low it had plenty of cargo room, too. This Yukon SUV is virtually useless for carrying long or large items. But then it was never intended to be a truck. It is a box shaped car on stilts.

An ironic commentary on the SUV craze came when it was revealed that Subaru had traction control in their station wagons because they knew they were being used by campers and hikers going off road while the SUVs lacked this feature because they were used exclusively in the city. This Yukon has one advantage over a station wagon which is that with the truck craze nowadays only someone sitting up high in a truck can see past the cars around them to see what is ahead. The second advantage is physics. This SUV is ridiculously heavy and will survive accidents with other oversized trucks being used as cars on our roads.

This SUV not surprisingly does not corner very well and is a hassle to park. The ride however is smooth and typical General Motors. GM always has ride quality well sorted out on their vehicles. They know this is going to be used as a car and worked out the suspension to provide a softer and smoother ride than many cars with firm sport suspension. There is no hint of the dump truck heavy springing jouncing found in trucks. Bouncing and rattles are absent from this SUV. The doors use full frames around the windows which seal out dust and noise very effectively.

This particular Yukon is stock except that the exhaust was changed to a performance system with low restriction Flowmaster mufflers. The Yukon is used as a city get around 'car' and is thus not pushing it's square box frontal area through the wind at high speeds which really messes with mileage. The strain of moving all that mass out from intersections from a stop does take it's toll on MPG and acceleration. The truck is filled with Chevron 94 octane which is free from ethanol. The fills below were made during a trip with some stop and go combined with 45 MPH open road cruising.


Kilometers Gallons      MPG (uncorrected)

266,085.5   19.0         n.a (needle moved from 1/4+ to F)

266,114.7     3.0         6.0 MPG  (18.1 miles)

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