i got a 2002 gmc serria 5.3 z71 its got 4.11 gears but it has no low end it will not even spin the tires what can i do to get some more power below 2500 rpm

 

Its probably a factory computer setting to get by the EPA requirments. Both my 01-06 are weak on power. My firend has a 5.3L and is big on chevy and always talks about upgrading to a power chip so that might be your only solution.

 

I had a '99 w5.3 3.42 RR , Installed a cold air intake, trottle body spacer (which is suppose to really help on low end). and 3" performance exhaust. It really made alot of diffence!

 

Get a predator programmer or a custom tune to reduce the Torque Management. This will give you plenty of torque and save some gas as you won't have to floor it to take off anymore.

 

Check to see if your truck has the G80 Locking Rear-end option, if you do then it will take a tremendous power increase to spin them rear tires.

 

it does have a losker in it im replacing the diff bearings tonight but it would spin them when i got it and it had 305/70/16 now its got 285/75/16 which is there not as wide so it should still do it right?

 

will a super single (3" with a vortec muffle) and factory chip reprogram give it more bottom end? Mine idles rough would it change i emissions enough to make that go away?