asap216

i am currently looking at an 03 4 door 2wd 6.0l truck thats used with only 83k miles! i test drove it today and i noticed a few things that came to attention. first off the idle seemed like it would sit their and bounce but then after i drove it and it warmed up it stopped. the second thing is the fuel pump is making a whining noise but if i get the truck i will just replace it. i am more worried about the idle problem. i was told that it could be a collapsed lifter or something of that nature. other than that the truck is in amazing condition. it actually appears to have an allison transmission and a 14 bolt rear end. any one have any ideas about the idle?
thanks in advance!

wld1985

iTrader: (1)

Could be a dirty throttle body...Might need a tune up soon, I've got the reg. 1500 verison but I didnt' tune mine till about 110k miles... Also the fuel pumps tend to whine sometimes, espically if the fuel is low..I'm around 130k on mine and its still stock..But whine's everynow and then..

2000chevysilverado

iTrader: (11)

The fuel pump is pretty much normal with gm trucks everyone I've had did it and they never gave up

AKlowriderZ71

iTrader: (22)

The noisy fuel pump might be caused by a plugged fuel filter. The extra restriction will over-work the pump, and can eventually burn up the pump motor. If you purchase the truck, replace the fuel filter right away. But be prepared to replace the pump if it's still noisy.

If the truck has a 6.0, then it should have the 4L80E. The Allisons were only put behind the 6.6 or 8.1 engines as far as I know.

With the age of the truck, and the idle that you asked about, I'd also recommend a new set of plugs, and a Motorvac injector flush (or equivalent). Also wouldn't hurt to clean the throttle body.

asap216

thanks guys i just talked to a guy thats pretty knowledgeable about the engines and he said it might be the cats too. if i buy it i am going to put new plugs, wires, and fuel filter. i will go from their if it is still acting up

Mangled03gmc

iTrader: (95)

Everything AK said. As far as knowledgeable, your not going to get too much better then the folks round these parts

asap216

the guy is actually a member of this forum and has a procharged 6.0l lq4.

asap216

i think the noise your talking about a very high pitched tone almost like those annoying "dog whistle" ring tones. this one sounded much duller and sounded like it it would speed up then slow down. constantly.

2000chevysilverado

iTrader: (11)

Like stated before changing fuel filter is always good i dea with new truck fuel pump just buy one and replace it if you are worried bought it never hurts to put new parts on just expensive

asap216

now that i have been researching it.. around what do yall estimate my mpg? i have been looking and people are saying they get in the 13's quit often and that worries me lol. i figured it would get atleast 16 on the highway since its a 2x4