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Showing results for tags 'fixing mpg'.
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Hello, I’ve got a 2008 GMC Sierra SLT with z71 package. I’ve had it stock until this year (2020). Recently put a level it in and had the truck aligned and it ran great. Went to put new tires and rims which are 33x12.5 Toyo open country AT2 extremes on 18x9 fuel assault wheels. The truck obviously had a decrease in power and mpg but recently it has gotten significantly worse. On HWY I can get 18-16 but recently in the city I am getting 11mpg!!! I live in a city with a lot of hills and windy driving so I can attribute that to some of it but it seems low. I’ve looked around and some guys suggest checking air sensors and tune ups, but I am wondering at what point is it a bigger issue? Or is it the reality of a lifted truck with heavy tires? any suggestions are welcome, it has not been 11mpg for long just the last month. Thanks
Bad mileage for 5.3 Silverado
trentkoch123 posted a question in Ask the GM TechnicianHello, I have a 2001 Chevy Silverado 2500HD, It has a 5.3L V8 Vortec engine with 288,000 miles on it. It has 265/75/R16 AT tires, Things that are original include 6/8 ignition coils, MAF sensor, fuel injectors, serpentine belt, ect sensor (ive heard of problems?) Things that have been done to the truck since I got it include Radiator and water pump, hoses, heater hoses, Spark plugs and wires, fuel pump and O2’s in October 2017. 2 new ignition coils (The other 6 are stock) Oil changes/new air filters, Valve cover gaskets, (Used Throttle body cleaner and MAF cleaner about 1.5 years ago) When I 1st bought the truck in late 2016 was getting around 13-15 hwy which was good for me at the time. About 6 months in, the fuel economy started to decline, though it was not overly concerning to me yet, but within the last 6 months (around September of 2019) it took a hard hit. What was a decent economy, I only get 9 or 10 miles a gallon on the freeway, and don’t even get me started about the atrocity that is city driving. However, I have noticed that my Long-Term Fuel Trim on both banks is anywhere from 14-18% no matter when I check it, hot or cold, idling or at 2000RPM. No one has been able to give me any direction on how to recover any mpg's so far. I use the truck for work daily, I do a lot of driving, but still, it shouldn’t be so low! I just need some guidance here, as to where to (re)start as for fixing this thing. Thank you so so much if anyone has any types of input. Please help! somebody! Thank you
Poor MPG for 5.3L Silverado
jrucsky posted a question in Ask the GM TechnicianHello, I have a 2000 Silverado 1500, 3.73's, 285/75/16 AT's, K&N intake & duel Flowmasters exh. The truck has a 4" Rancho susp lift that sits at about 2.5", and has rear leaf's from a 2500. Currently apprx 118k miles on it. I love the truck and trust it enough to go anywhere in it. When I 1st bought the truck I was getting around19-20hwy. Lifting it cost me 1-2mpg's, so I was getting 17-18hwy. At about 50k the MPG's dropped dramatically. I started getting at best 15mpg no matter how easy I took it. I had everything I could think of looked at. I had two Carbon flushes done to it by the dealer, changed plugs, Flitters, tranny serviced, rake added to the front, pumped tires to max. I've really tried everything I could think of. No one has been able to give me any direction on how to recover any mpg's. I use the truck for work daily, I do a lot of driving, and as of the last 30k miles I've been getting no better than 12mpg's on my mixed use tanks. On the tank I'm on currently, its looking like I'm heading for about 10mpg's, And I've had enough!!! I love the truck but there is no reason a light use of a 1/2 ton should be getting big block type mpg's. Can anyone please help!!!!? I was told of a kit called something like a spyder injector kit, that swaps out the injectors. When I search I find stuff for the old 5.7's and 4.3's but nothing on the 5.3L. I don't expect to get great Mpg's out of a truck driven in around the city, but 10-12 is rediculous! I don't want to sell the truck but .55/mile doesn't ease the pain of 10mpg's. I mean if that's all the better I'm gonna expect I should at least go get a 2500 or 3500 with a big block, cause then I can actually work the truck. Please Please Help! Thank You