2001 Silverado 5.3. *WEIRDNESS*

[HanibalTheCannibal]

Well, I have 49,000 miles on this truck. I recently noticed a significant drop in MPG. From 16-12 with no change in my driving habits. I heard what I thought was a spark *pop pop pop* so I chenged the plugs, wires, fuel filter. ACDelco Premium wires The good ones ($70). Noise is gone, but I have noticed that it still has a teeny weeny bit of a shake to it. How much shake is acceptable?
Here is what I Have done since I bought the truck last year with 33K miles:

1. Full GM transmission service (flush, filter, gasket)
2. Full B&G Fuel service (4 part pressurized decarboning system)
3. New fuel filter, plugs, wires. (Air filter is good and clean)
4. No other mods, all stock.

As I hit the 50K mark, what other things should I change? This truck only accumulated 33K in 5 years, and the lady may not have had anything done, except oil changes.

Should I change the O2 sensor? How many are there and what do they cost?

Any other suggestions to get my MPG back? Is this because of the "summer Blend"?

Thanks

[2000CAYukon]

Is the shake while driving or at idle?

My 2000 Yukon only has 33K on her and I have not had to change the 02s.

I did however need to clean the TB last year. It was pretty dirty and ran much better after a good cleaning.

//2000CAYukon

[motorman24]

I have a 2002 Chevrolet Silverado light duty 2wd. What is the tallest tire that can be put on the stock 16" rims.

[HanibalTheCannibal]

Originally Posted by 2000CAYukon

Is the shake while driving or at idle?


//2000CAYukon

The shake is at idle. The 4 part B&G system included a TB cleaner.

Any thoughts

[2000CAYukon]

Originally Posted by HanibalTheCannibal

The shake is at idle. The 4 part B&G system included a TB cleaner.

Any thoughts

Fuel does not go thru the TB so they needed to clean it separately. On mine there was obvious carbon build up where the throttle blades met the TB.

You should visually inspect the inside of the TB to be sure it is clean.

PCV valve might also be a good thing to replace at 50K miles.

//2000CAYukon

[HanibalTheCannibal]

Originally Posted by 2000CAYukon

Fuel does not go thru the TB so they needed to clean it separately. On mine there was obvious carbon build up where the throttle blades met the TB.

You should visually inspect the inside of the TB to be sure it is clean.

PCV valve might also be a good thing to replace at 50K miles.

//2000CAYukon

Yes, it was cleaned seperately. the 4 part B&G kit had a tank treatment, a TB cleaner, a Pressurized Fuel rail cleaner, and another Pressurized Intake(?) cleaner.

It was sprayed with the cleaner. I will give it another look. I have heard that sometimes it takes two decarbonization kits to do the job. It had to be done with a special pressurized chemical injector.

On a side note, after we did the 4 part kit system, We looked at the plugs and oh man they were thrashed. I have had plugs in other vehicles for 40-70K miles and these in my truck were at 43K and the were gone. I mean the points were eroded, and they were very bad looking. So we changed them.
I got to thinksing since we did that cleaning that I may have "gummed" up the O2 sensors with all the carbon that was released from the engines intake system and fuel rails etc. The exhaust was very nauxious (nasty) made your eyes water

[2000CAYukon]

If you decide to replace the 02 sensors, remember that the sensors before the cat is used for air/fuel ratio. The sensors after the cat are only used to monitor the system. I can't remember if we have 1 or 2 cats (I have been working a lot lately on my 90 K1500 that only has 1 cat).

Hopefully the 4 part B&G kit is 02 sensor friendly.

//2000CAYukon

[HanibalTheCannibal]

Originally Posted by 2000CAYukon

If you decide to replace the 02 sensors, remember that the sensors before the cat is used for air/fuel ratio. The sensors after the cat are only used to monitor the system. I can't remember if we have 1 or 2 cats (I have been working a lot lately on my 90 K1500 that only has 1 cat).

Hopefully the 4 part B&G kit is 02 sensor friendly.

//2000CAYukon

It is GM dealer "approved". It is not even for sale to the public that I know of. I had to buy it from the delaer. I tried all the local parts stores (8 of them) and it is not all that expensive but I guess they know that most people do not have the $1200 B&G presurized canister injection-ator thingy.

I heard that if you look at one it should have ablusish tint to it. If not, then it probably needs changing. DO you know the reccomended interval for changin the O2 sensors on these? I will try to google the service intervals for these.

[2000CAYukon]

I've heard 100,000 Miles for 02 but I have heard of them going bad before that.

Did the problem start after you heard the "pop pop pop"?

//2000CAYukon

[HanibalTheCannibal]

Yeah, I have always noticed a little miss. Maybe the wires were on their way out.

My main worry is the sudden drop in MPG now. I am gonna watch this tank and see how it goes. I am getting married this weekend and have a honeymoon vacation, so we will get some highway miles logged.

[2000CAYukon]

Originally Posted by HanibalTheCannibal

I am getting married this weekend and have a honeymoon vacation, so we will get some highway miles logged.

Congratulations! Enjoy the honeymoon!

//2000CAYukon

[TexasF355F1]

I would say the fuel pressure regulator needs to be replaced. That tends to be reason for rough idles in our trucks.

[HanibalTheCannibal]

Originally Posted by 2000CAYukon

Congratulations! Enjoy the honeymoon!

//2000CAYukon

Thanks!!

Hey, Texas..... What do those things cost? SHould I get GM Brand (AC Delco, etc)

Thanks!!

PS Truck runs a lot smoother with the new ACDelco wires. The ones on there were called Pegasus(?) very thin and flimsy..

[masapell]

Originally Posted by HanibalTheCannibal

PS Truck runs a lot smoother with the new ACDelco wires. The ones on there were called Pegasus(?) very thin and flimsy..

Hannibal,

I have been thinking about doing this myself. Where did you get the wires, and how much did they cost you? How difficult was it to do the plugs? Thanks,

Matt

[HanibalTheCannibal]

You have to go to an Authorized ACDelco parts house. Autozone, Advanced and O'Reilley's will not have them because they are so high, people will usually buy the $20 set. I paid $68 after tax

**AND** you get a lifetime replacement warranty

Just call around and ask for ACDelco wires. They will want to know if you have "Delphi" Or "Munsen"(?) wires (Both of which are ACDelco). The Delphi are the shorter ones, the other are a bit longer. My 2001 Silverado 5.3 used the shorter Delphi wires. You can look on your plug wires right where they enter the coil. Unplug one and look around for the name "Delphi" or "M______". (<--- cant remember the other name)

You have to twist on the boots at the spark plug to free them first. Then grab the metal boot cover part and the plug boot to remove. I used an up and down motion while pulling them off. It is kind of a pain, and you might want to wear some gloves, you will most likely bang a knuckle on the plugs next to the firewall. The silver metal part comes off WITH the plug wire. You then pull the metal cover off and place on your new wire then install the new ones.

You want to install the wire on the Plug *FIRST* before you plug into the coil/ This prevents any pulling or straining on the coil assembly. It only takes about 20 minutes to do all 8. I noticed a much smoother idle and acceleration. I guess that is how you know it needed them

*PS Do one at a time so you dont get them all mixed up.