Hey so I've got a 98 2wd 24 valve auto trans and 3:55 rear end tires are 265/75 16 I've got an Airdog 100 a B&M air intake and a 4" turbo back straight exhaust also running a smarty on economy and timing set to 4 and my mileage seems to be low for what I've been reading drove up north and got 22 then made a trip to the coast and was at 18 going 55 mph the whole way city I'm at 15 ish was thinking my injectors could need to e pop tested or replaced truck has 112k on her any ideas?

 

You might try adjusting valve lash.

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Thats not bad mileage. Thats what I get but mine is 4x4. Are there a lot of hills where you're at?

 

Auto or Manual?

 

that seems a little low to me. my 6 speed with 4.10 gears rarely sees any highway and i still get at least 18mpg.

 

its an auto i just had valve lash done and she was dead on 10 20 when i was driving on flat land up north it was 22 ish but to the coast there were a few passes where i was boosting from 5-10 ish it runs good idles at 800 in gear and 900 or so out of gear i get a puff of black on start up and noticed a little haze this morning when it was warming up other than that driving around town i dont see any smoke at all unless i get on a little hard and that was when it was stock it would smoke with a chip it might do a little more but im not after smoke im after mileage from all the tall tells of these guys with 2wd getting 18-20 city and 24 fwy

 

i forgot to mention that my truck is a 4wd.

 

yeah see! your hauling an extra axle transfer case drag and still doing better than me i know something just isnt right but cant exactly figure it out my best guess is injectors? im probly not getting a good spray at the right time or something i just wanna make sure before i tackle pulling them out

 

could be i have no idea, someone on here is smart enough to tell you were to look first. im sure you can get way better fuel mileage than that

 

Yeah just waiting for a genius to chime in

 

Have you changed trans fluid? Most of the guys that get higher fuel mileage with autos have built tranys. Even just putting an upgraded valve body in will increase mileage. Then there are the guys that say they're getting the mpg that the overhead says which is never true. On hwy my overhead says I'm getting 27 but its really 22 hand calculated. I've never used a smarty but I'm sure if you play with the settings a bit you can do better. Might even try a performance tune. I get my best mpg when my edge is set on extreme performance and I drive with a light foot.