Why are 5.3 dogs?

[Donnie Yukonie]

I have an 03 Yukon and was told by my mechanic that the intake manifold was leaking causing it to lose power. It's fine around town but when I hook up my trailer (2800#) it really drops off the power. Anyone else have this problem? Pulling the trailer I'm getting 9-10 mpg. I bought it because I was told these trucks would pull a house down. ???????????????

if you got the 5.7 yes it is leaking almost all did mine was leaking bad not a bad time to change the spider injectors while your in there WORLD of difference just had mine done 2 weeks ago

 

[02tahoeindiana]

if you got the 5.7 yes it is leaking almost all did mine was leaking bad not a bad time to change the spider injectors while your in there WORLD of difference just had mine done 2 weeks ago

He said 03 Yukon, only 5.3 or 4.8

 

[DarylinB]

Intake Manifold Leak, 2003 Yukon 5.3

Would the leak cause the power loss and poor mpg (9-10 mpg)?

---------- Post added at 09:00 PM ---------- Previous post was at 08:58 PM ----------

What type MPG should I expect with the 5.3? I was hoping for 15-17 mpg, maybe 15 towing the trailer.

 

[Donnie Yukonie]

He said 03 Yukon, only 5.3 or 4.8

wow i totally didnt see that im an idiot

 

[94z28guy]

I know when one is faster than others and I know the difference between LS motors and non LS. Ive spent the last 10 years building LS1's and LT1's. I really am starting to believe its the tq management. After playing with the the 01 some more its only slugsh between idle and 3k, after that it feels strong. It just isnt making power down low. As far as the .8 in a quarter as previously mentioned keep in mind that was a calculators esimate and not real numbers. Calculators doesnt consider tq management. Lets put it this way, while in drive im 3/4 throttle every where I go just to keep pace with traffic. Im going to try and change the plugs. Air filter and fuel filter is new. Mass air is clean and throttle body is decent.

 

[02tahoeindiana]

wow i totally didnt see that im an idiot

haha all good bud, i wish you could have ordered 6.0s on these!

---------- Post added at 10:50 PM ---------- Previous post was at 10:46 PM ----------

I know when one is faster than others and I know the difference between LS motors and non LS. Ive spent the last 10 years building LS1's and LT1's. I really am starting to believe its the tq management. After playing with the the 01 some more its only slugsh between idle and 3k, after that it feels strong. It just isnt making power down low. As far as the .8 in a quarter as previously mentioned keep in mind that was a calculators esimate and not real numbers. Calculators doesnt consider tq management. Lets put it this way, while in drive im 3/4 throttle every where I go just to keep pace with traffic. Im going to try and change the plugs. Air filter and fuel filter is new. Mass air is clean and throttle body is decent.

Thats TM, you can really feel it let the reigns out after 2500-3000 rpm in my truck. But the fact that you cant keep up may be prior owner lack of care and maintenance. How many miles does it have? But thats doesnt mean much with SBC's, mine has 189k and is strong is ever.

 

[94z28guy]

It has 200k on it. BUT the 97 also has 200k.

 

[bowtiefreak]

I got the chance to race a 2003, maybe 2004 tahoe in my tired 1997 suburban a week ago. I have a tap and a bad knock and beat it by a fender (when I say a bad knock and tap, there are days I have wondered how it drive home.) My suburban is all stock motor wise witha 87 octane BB tune and a flowmaster muffler. That and 4.56 gears....and bigger tires.

By no means is it a fast truck but I have also driven my dad's 2003 and it does feel sluggish.

 

[94z28guy]

Put some plugs in the 01 today, although they looked like hell because they were factory. (Hoe has 200k) New ones didnt help the sluggish part any. I put TR55's back in it gapped at .055. The old ones ranged from .065 to .085. Ill prolly get the tune next, this sluggish feeling sux. Gotta love old school 350's for raw power (in the trucks). I know LS1's in the cars are touched by the hand of god haha.

 

[hoe]

my 5.3 was not a bit of dog at all. Its about the driver, and maintance. Example gears etc, whats comboed with it.

I pulled my perfectly good motor, just cause Im a hotrodder.

I have a LS Vortec Max 6.0, 4l80e, 4.56s gears, 3700rpm 9.5" billet stall, LPP long tube headers, cold intake by AIRAID, street tuned by PCM4less.

IMO what you would call a race, is a mute point to me. I have yet to run into someone on the streets that wants it, and I race newer hemis all the time. a OBS motor is no comparison to a LS motor.

That said, I have lots of OBS motors, 383s, 408s... and they are highly modified as well. and IMO i love my LS!

you guys are still comparing a 350 to a 5.3? thats ridiculous.

Just a tune of the computer on a stock 5.3 and all games are over in a stock form. no comparison.

the GEN1 have nice lowend, true, but GEN3s have a nice pull on the top end. And still end up wining the race at the line.