Just had all 8 replaced a couple of weeks ago. This past weekend I finally got to go on a long trip (500+ mile). I got the attached pic at the half-way point. It was reading 24 a couple of days before I took the pic, but I did some in-town driving before remembering to get the camera.

Previously to the injector service, I was getting only slightly better than 20 MPG.

All I can say is "Why didn't I go for new injectors sooner??" (Not Really!)

Can new injectors actually increase mileage this dramatically? I never got this good of mileage with the old ones, were they defective from the start?

L8r

That is impressive if you are stock. I still would like to see it hand calculated to confirm.

wow, I wish I could get 20 with blown injectors

100% stock...

Before the service, the calculation difference between the DIC and hand were only off by at most 3-4 tenths.

I guess I should do another hand calc just to confirm the DIC's numbers. Can't do that now as I have shut off the Personal Log...

L8r

a lot of guys are getting 20-22 on the highway(lb7) with an automatic so i believe your mileage is definitely possible considering you have a zf 6 speed. wil

Does my Duramax do that? Or was it an option? I've never seen anything like that on my screen. LOL

Does my Duramax do that? Or was it an option? I've never seen anything like that on my screen. LOLI think only w/steering wheel controls.

I have gotten as good as 24.5 on an Interstate trip at 65-75 steady. I think my cap improves aerodynamics over an uncapped crew cab.

likewise...just the other day i saw in the 24's but couldnt keep my foot out of it for too long

Best I could do

I did a long highway trip on Sunday and set the cruise at 67. At the end of the trip I averaged 23.1 mpg with hills and flats mixed in.

I have those dreams right now. I get about 17.5 in town. I am in construction and my truck sits and idles alot. I need to take my LB7 in and have the injectors checked. Lots of little noises. It only has 48K on it, still want new injectors...:)

GEEZ, I only get 14.5 mpg! And that's when I drive like grandma! Maybe I need to take it to Chevy to have them check the injectors...????

Three weeks ago I noticed that my truck started to stink a little. It didn't really bother me, but it did keep tailgaters back about a hundred feet. There wasn't any serious smoke, drop in mileage, excessive rough idle or diesel in the crankcase. Just that noxious smell when I got out of the truck. I finally took it to the dealer on Tuesday morning. They diagnosed the problem Tuesday afternoon, replaced all of the injectors on Wednesday and Thursday. I picked up the truck today (Friday) and it runs great. The highway mileage ia still around 22.2 mpg at 65 mph. The same as before. City Checrolet in San Diego has always been fair, honest, informative and most of all truthful in their service work on my truck. After reading all the injector posts on this forum over the years, I was expecting something painful!

Well I am going to take mine in next week lets hope is goes as well as yours did....

I guess I should feel lucky getting 16 MPG in the city and 6.5-8 MPG towing.
I have taken mine to the dealer and they told me my injectors are fine. I think I'll demand a change.

I got 22.3 when my truck was almost new at 70 mph. Got injectors at 43,000 mi. less than a year ago, drove 4,000 mi. over this holiday at 80/85 mph. and hand calulated got 19.8 mpg. I can live with that!

I got 22.3 when my truck was almost new at 70 mph. Got injectors at 43,000 mi. less than a year ago, drove 4,000 mi. over this holiday at 80/85 mph. and hand calulated got 19.8 mpg. I can live with that!

I took my truck into Chevy today and they called and said they are replacing the injectors. I can't wait to get it back and see what kind of MPG change I get...

I get around 14-16 mpg average. Truck has 109,966 miles on it original injectors. I guess my question is how do you know if you need new injectors? Does the dealer tell you if you need them or you just decide "Hey I think I need new injectors" and then you have them replaced at the dealer. If I am the second owner of the truck, do that 200K injector warranty cover it or not? Please advise.
Thanks alot

The dealer will do some testing and determine if they need replaced. If they are ok they will charge you a service charge I would guess. I think you will be covered under warranty if they are needed.

The dealer will do some testing and determine if they need replaced. If they are ok they will charge you a service charge I would guess. I think you will be covered under warranty if they are needed.

thanks):h

I've seen 25 mpg the first time I chipped my truck driving 55 mph on flat land-- about a 100 mile trip. stock, it only does between 20-21. Had four sets of tires so far.... and found winter tires dramatically decrease MPG. I can only get about 17 for the same stretch without chip.

I suspect if you got aftermarket injectors they are ballanced. The stock injectors on my motor are matched within like ~13% the aftermarket guys often use much tighter specs closer to 2% across all cylinders. This is really true if you're going bigger even a little. I might be wrong, I don't think so.

Ive got 14 since about month 6 and on. Used to get 17-19 new. Not for a long time have I seen those numbers.......

I get around 14-16 mpg average. Truck has 109,966 miles on it original injectors. I guess my question is how do you know if you need new injectors? Does the dealer tell you if you need them or you just decide "Hey I think I need new injectors" and then you have them replaced at the dealer. If I am the second owner of the truck, do that 200K injector warranty cover it or not? Please advise.
Thanks alot

I just got my truck back today. The dealer checks the flow rates on all. I had two out of the eight with high flow rates. Plus there was fuel in the oil. They have replaced all injectors

Did the warranty cover the injectors? I have one thats putting out too much and one that's the opposite. They told me it was in the electrical and not bad injectors. They want $ 1900 to fix them. There's one on each side. Bad news the ext warranty won't cover because they're not damaged. I'm going to check around first.

I just got my truck back today. The dealer checks the flow rates on all. I had two out of the eight with high flow rates. Plus there was fuel in the oil. They have replaced all injectors

Do I just ask them to do that?(check the fuel flow on all injectors?)
Then, after checking, if something is wrong, do they just go ahead and replace them all? I am assuming there are covered under warranty. Truck has 100K miles and some change...

I just got my truck back from the dealer. They replaced all the injectors. I had an oil pan full of diesel. Chevy covered the cost of the work, the injectors and towing. So far the truck sounds better, I will let you know on the fuel mileage.

just picked up my truck last night. when I brought it in I let the Dealer know I researched my problem. Rough idle, knock under load, and smoke at idle. He knew that I knew it was a warranty issue. They replaced all 8 injectors, Fuel filter and changed oil (diesel in oil) he charged me a $100 deductible but later said that was a mistake and refunded my money. So far truck runs good. No smoke knock is gone. I am still questioning the idle but I think I am to critical. I know I can probably get the TSB about the injectors somewhere for you...

I brought mine in for visible smoke, suspecting injector failures. The dealer diagnosed the problem but had to order the injectors, so I took the vehicle back while they were waiting for them and noticed an increase in mileage returning from the dealer vs. on the way there. Apparently, they did some reprogramming in the course of troubleshooting the injector problem, and this is the source of the mileage improvement, not the injectors (which hadn't been changed, yet). After having four changed on one side, mileage has stayed up. Dealer confirmed that it was likely due to reprogramming. Wish I had THAT done a bunch of miles ago, would have saved a lot of fuel!

Clark20ry, Who did the work? Lou Grubb, (Power chevy) now, 27th. ave and Camelback did mine.

Clark20ry, Who did the work? Lou Grubb, (Power chevy) now, 27th. ave and Camelback did mine.

Power Chevy on 91st Ave and Bell...

Did the warranty cover the injectors? I have one thats putting out too much and one that's the opposite. They told me it was in the electrical and not bad injectors. They want $ 1900 to fix them. There's one on each side. Bad news the ext warranty won't cover because they're not damaged. I'm going to check around first.
I took my gmc to chevy and they said the solenoid was part of the injector and replaced all eight under warranty. Now I have 12 months or 12000miles. Also some parts like starter and alternator ( I think) have a lifetime warranty.

Ok guys I have a stock 02 4x4/allison and cant get over 18mpg. I would love 20+ Any suggestions??

a lot of guys are getting 20-22 on the highway(lb7) with an automatic so i believe your mileage is definitely possible considering you have a zf 6 speed. wil

I haven't seen where the zf gets any better than the ally.

I have an '02 Crew Cab 4x4 D/A with 65K on it.
The best mileage I've ever recorded was 20.5 mpg.
I usually get 16.5 city, 18.5 hwy. To get 20+ mpg you have to accelerate like a normal human, drive 55-60 mph with NO A/C on, no towing (obviously), tailgate UP (not down). I rarely do ALL those things combined...

I have an '02 Crew Cab 4x4 D/A with 65K on it.
The best mileage I've ever recorded was 20.5 mpg.
I usually get 16.5 city, 18.5 hwy. To get 20+ mpg you have to accelerate like a normal human, drive 55-60 mph with NO A/C on, no towing (obviously), tailgate UP (not down). I rarely do ALL those things combined...

I took my gmc to chevy and they said the solenoid was part of the injector and replaced all eight under warranty. Now I have 12 months or 12000miles. Also some parts like starter and alternator ( I think) have a lifetime warranty. I was told by my buddy @chevy parts dept that if i bought the injectors & installed myself, or had installed by anyone other than GM, the warranty,was only 120000- 12 month, they(dealership) wanted over $2500 & would supposed to be lifetime, my truck @ the time had 8 months(70000 on the 3 rd set of inj, but truck was over on miles (236000), with GMs injector track record, i decided to buy an engine from canada, 11000 miles $3900 , so far it runs great, & i still have my old engine....fingers are crossed,hopeing to get at least 50000 miles on this one, just added hypertech 90 hp , have EDGE J/A will add in a couple of more weeks , also will install 4" jardine EXh , just adding in stages , monitoring MPG right now between add ons.. BTW i installed a MIDWEST CONVERTER quad disc, trans will be upgraded in next couple weeks also , dont think the next 50000 mile will be easy miles;)

I've got an 03 4x4 with 265's. otherwise stock. the best i've ever gotten for a trip was 18.9. i haven't seen that for better than a year. If i get close to 70 mph, i'm only gettin 16. i've checked it by hand to see how accurate the trucks computer is, and it's within 2 tenths for the tankfull.The only time i see 20 or better is if i look at the instant mileage at around 55. How come there is such a large gap in mileage? I don't beat on my truck.

I just got my truck back from the dealer. They replaced all the injectors. I had an oil pan full of diesel. Chevy covered the cost of the work, the injectors and towing. So far the truck sounds better, I will let you know on the fuel mileage.

Got mine back from the dealer, It ran great the first tank and the mileage checked 18MPG. Best I have ever seen. Next Tank back to 16 MPG.