sup guys...i have an 02 4.8 ecsb silverado with 64xxx miles and lately i have been noticing a rougher than normal idle...i have replaced my fuelfilter (thinking it was that causing the idle) about 1k miles ago and my air filter is still good...not too long ago i had my throttle body de-carboned (or whatever you call it) and a fuel injector flush...the only thing im thinking it could be is my fuel pump...could it be anything else? the truck starts to idle rougher when im like stopped at a light for more than 10 seconds...

 

Possibly plugs or wires

 

do i just simply check the plugs by pulling them out and checking the gaps? how do i check the wires?

 

At your mileage, I would strongly consider replacing plugs and wires. I personally run NGK TR-55 straight copper and replace them every 30K. I also went with Taylor wires.

 

Use the throttle body cleaner and clean your MAF sensor. This is a big cause of rough idle as well. Make sure the TB cleaner is not oil based. You want a cleaner that dries almost immediately upon contact. Do not wipe the inside of the MAF sensor as you could damage the small fine gauged wires. Just take it out and give it a good cleaning on both sides.
Another thing could be the EGR or a really oily intake manifold.
Go a head a give those plugs and wires a change as well. go back with the O.E. plugs and wires. They will work best for you.

Jim

 

Check the fuel pressure regulator as well. It is in the middle of the driver's side fuel rail and has a vacuum line going to the intake manifold. Pull the engine cover so that you can see the regulator better. After the truck has recently been driven pull the vacuum line at the regulator end. If the line is wet with fuel then the regulator is damaged and will need to be replaced.

 

i will check all these things when i get a chance, thanks guys

 

should i just bring my truck in since it is still under warranty? (7yr/75k) the plugs are supposed to be good for 100k..supposed to be...

 

If it is under warranty then I would definately bring it in. I doubt they will change your plugs because GM tells them they last 100,000 miles.
Just bring it in to the dealership.
Don't waste your money on it if you don't need to.
Jim

 

if its under warranty yea bring it, you could also run a can of sea-foam...that usually cleans up your idle, through the brake booster line or whatever