My friend ha a 99' ec 4.8 Z71, here recently he tells me its acting sick. After it sits a few minutes and he goes to start it, the truck idles down- then acts like its bogging down(rigt after yu start it).He also said in the mornings when he leaves his house it hesitates, like it's missing. I asked about plugs-wires, he told me he changd the plugs about 3 months ago(bosch)no wires still stock.The only thing done performance wise to the truck is dual's.He's guessing the fuel pump might be going bad, but i thought that when a fuel pump goes bad it dies right then? He also asked about a fuel pressure reggulator? Can he adjust it, or is that done by computer? Or does he just have crappy plugs, and need a tune up? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

 

put sum gas in it ...mmmmmmmhhhhmmmm. <img border="0" title="" alt="[Razz]" src="gr_tounge.gif" />

 

it could be a million things. How many miles? Mabye is the fuel filter, or bad gas. the smartest thing to do is to go to the dealer and scan it with the GM Smart Tech 2 itll most likeley be able totell u whuts wrong.

 

4.8 z71? i thought z71s were all 5.3? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

 

Nope - there are 4.8 Z71s.

There was a picture on the net a while back of this huge lifted Z71 with like 38" tires. But in the truck description, it had a 4.8 liter and I think the stock 3.73s.

Neil - where is that picture? I know you can find it - you da man.

 

crazy cracker. you been smoking that **** again? <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" />

 

The truck has a little over 60k, he said he never runs low on gas or anything...so it's not that, the only problem with getting it checked would be that the price to git it scanned would probably be more than a fuel filter or somthing small like that.But if thats what he has to do... i guess he'll be paying a visit to the ole dealership!!

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by RED2K:
<strong>crazy cracker. you been smoking that **** again? <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">bbbbbbbooooooonnnnngggggg

no i haven't. they can't make that many 4.8L z71s

 

Check the air filter, change the fuel filter (like 10 bucks), inspect the MAF sensor, look for anything out of the ordinary under the hood, like damaged wires, loose connectors, etc. Change PCV valve (needs changing anyway), make sure the belt is tight, if none of those work, get it scanned. Autozone does it free, but I am not sure if it will work on our trucks??? Does this problem go away as the truck has been running for a few seconds/minutes?

 

He just said that in the mornings it does it, and after the truck has been sitting for a matter of 10-30 minutes, ive heard it when he starts it up ,sounds like it drops rpm's real low then try's to lean itself out or somthing,kind of like it's boggin down as soon as you turn the key.Ill pass on those tips...hopefully one will work.