'00 Sierra a little rough after starting

[spikefish]

I have a '00 5.3L Sierra, great truck, and no problems after 68,000 miles. Of those miles, about 10,000 is pulling a 6,000 pound TT.

 

For the last month or so, the truck doesn't start as easily, and runs a little rough when it catches. After about a minute, it levels off and runs well.

 

I changed the fuel filter about 10K miles ago, and keep up with my maintenance. Could it be the spark plugs? I checked the manual and it said 100,000 miles for plugs, which seems a long time to me.

 

OK---Any suggestions? Plugs, fuel treatment, or some little secret you guys know?

 

If plugs, any suggestions on brand? I historically have used Champions for the past 50 years.

[rjirvine]

The Platinum plugs are stock with a gap of.060. They're superceded by iridiums with a gap of .060. I would stick with AC Delco only and stay with the platinums.

[svensk]

I think its time for a tuneup. Since it has only 68k miles it hasn't been driven very much and that makes a difference. I would go out and drive it daily for a week or two, pound on the throttle a bit see if it fixes itself. These trucks like to be used daily, and even trips under 10 miles a day might not be enough the let the engine heat up to full operating temp.

[MustGoFaster]

could also be carbon buildup on the TB plate and on the intake. From experience I can say that I have yet to see a set of plat's make it to 100k. most of the time I woudl say in the 75-80k is when the combination of carbon, degredation, fuel deposits, and general wear and tear start to add up to the point where you get regular misfires.

 

That being said, a general tuneup will work wonders.

I would suggest a Top End clean, then really scrub out the TB intake and throttle plate, (toothbrush baby! - my 01 silvy with 70k was really horrible) then plugs and wires. make sure you get OEM wires. Unless you go to some truly radical modifications they are simply the best trouble free units you can get. same of OEM plugs. While I will not get into a discussion of the (albedit documented) gains of some aftermarket equipment, there's a reason you haven't had to touch anything for 70,000 miles. OEM may only run at 98% of perfection most of the time, but it will do it ALL the time.

[svensk]

I had to clean my throttle plate out twice in the last two weeks because of a sticky throttle. very annoying.