i roughly get around 14-16 mpg in my rcsb z71 with the 4.8 wich i think is horrible,i mean ya its a v8 with exaust and CAI but that bad?

could it be my injectors and how could i check to see if there clogged? or wat else could possibly be doing and what should i replace?

 

I feel your pain as my cc gets 13-14.5 and I have added long tubes, cai, and tune

 

I get about 14 in the city in the tahoe below. What helped mine out (aside from the tune) is changing the plugs (TR55's), fuel filter, cleaning air filter, changing front o2's, and adding Techron injector cleaner to a 1/4 tank. You could also Seafoam your top end and clean your TB.

 

im alil new to some of this
how do i clean da TB properly and what do you mean seafoam my topend?

 

you should be getting better than that. my 99 5.3 with cam, 3000 stall, full bolt ons gets 14-16mpg

and my 06 4.3 5speed rcsb gets 18-21 mpg

im with TX tahoe, do all that and you should see a difference

 

Here you go! https://ls1tech.com/forums/general-m...-your-car.html

Edit: For TB cleaning, they have throttle body cleaner in a spray can at your local auto parts store, and come to think of it, might want to pick up a can of O2 spray cleaner as well and pull off the O2 sensor and spray it down carefully while you have the filter and intake tube off.

Edit Edit: To clean the TB, you can leave it on and just spray the heck out of it with the cleaner into the intake manifold (it all burns up in the engine, so don't worry). Put a brick on the gas to hold the blade open. Let it soak for about 15-20 min to really get in the intake and break the carbon deposits up.

Best of luck and post up here if you need any clarification or advice, we're happy to help!

 

pull your TB off and make it look clean. use some carb or brake cleaner and a rag and ge rid of whatever gunk you find. seafoam is an addative i belive you put in the gas tank, it's supposed to burn off all the carbon build up in your valve train(top end), and your truck will billow out tons of smoke while it dose its thing.

i have allways wanted to sea foam mine but i heard somewhere it was bad for the motor

 

damn that was a good write up. i think its time i seafoam my 168k mile 99

 

ya watever helps cuz im bought to hit 218k miles on my 4.8 but it still runs strong!!

 

thank you all much!!