02 yukon w/5.3 problems

YotaOnRocks

YotaOnRocks

Well-Known Member
Joined
Jul 17, 2007
Location
Madison
My wife has a 2002 yukon with 128k miles on it and for the last 3 years it has knocked at start up for 3-30 seconds after sitting all night. Sometimes it never even does it when its hot like in summer and always does it when cold in winter.

I was told by several people that it was normal for the 5.3 and don't worry. In the last week or so it has developed a miss at start up. It feels almost like it is caming. It goes away with knock and car runs great with no hesitation after that.

We plan to keep car for many more years so I am hoping some of you guys may have some insight as to what it might be. Thanks in advance
 
I have never done one and figure it wasn't done before we owned it. Bought it from dealer with 75k
 
plugs and wires are over due, 100k miles is the magic number, my wrk van made it to 110 before it HAD to be done.
you gonna spend $10 a piece for the plugs, use AC Delco, replace the wires as well,

they are known to rattle on cold start up, it's called piston slap, the piston is very short, and when cold it rocks in the bore a bit.

www.pistonslap.com some rather exaggerated info, but shows the extent of the problem

in the 4years I worked as a tech in a GM dealership there we 2 engines replaced for this issue, and then only because the customer raised holy cane with GM and the dealership.

Don't keep driving it with the misfire, you'll eat the cat's from running rich ( you'd be surprised how quick and sudden it happens )
 
Does brand of wires matter or just plugs?
 
I used the Carquest good wires, 10k so far no issues being coil near plug and short like they are it's not as serious as when strung across the top of the valve cover and intake when leading off a distributor.

I'll tell you I replaced more AZ/AA aftermarket junk to cure vain attempts to get a vehicle running, Factory parts are the best option most times. use the dielectric grease on both boots of the wires and be sure they click into place.

and if they offer you a high and low price option, look at both, a lot of times the wires are same but the box on the expensive wires it prettier.
 
Ok thanks. I'll try to do a tune up monday morn when I get off and see what happens.
 
New plugs and wires did the trick thanks vodoo
 
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