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Posted (edited)

my truck was throwing a code and it was really sluggish. got new cats installed and it was back to the normal slow 4.8 feel

 

also if you get new cats, have a new fuel filter put on

Edited by KMGZ400
Posted

+1,!! A fresh fuel filter is always a good start..And regardless if it was the problem or not..Its new and one less thing to worry about!

But the cats are important..Ive seen cats after 230,000 miles and they looked new. Also seen cats with 50,000 miles and 3/4 clogged,

Many things can get them shitty, Bad fuel, exhaust leak for a long period of time,etc...

Posted

My truck's a 2wd, so it's not suck in 4 hi.

 

I changed the fuel filter a few months ago, but I'll throw a new one on this weekend for good measure.

 

My next steps are:

1. Change the fuel filter again.

2. Try to find a good mechanic with a data logger/live data tool to see what's going on. If I can't find that, then:

3. Get the cats pressure tested

4. If the cats look good, change out the O2 sensors

 

This may take a week or so, but I'll reply back as soon as I make progress. Thanks for everyone's help!

 

On that note, do any of you guys know a good mechanic in the Austin/Round Rock, TX area?

  • 5 months later...
Posted

Digging this one back up from the grave because it is FINALLY SOLVED!!! The problem was a bad catalytic converter. I never had a check engine light or any codes. I heard some rattling one day, so I tapped on the driver side cat with a hammer, and it sounded like the thing was full of BBs. Replaced the cats, and my Yukon is running like a champ now.

  • Like 2
  • 7 years later...
Posted

Old post but I’m having the same issue as you 

@Juice75 I changed fuel pump fuel filter plugs and new wires changed tps and it just feels like Im driving up a steep hill 

going up hill is ridiculous i uave to floor it to stay at speed limit 

and same thing if I let off the gas it slows me down as if I’m pressing the breaks any update? Did you ever find a fix?

Posted
On 1/6/2021 at 9:45 PM, Slow4.8 silverado said:

Old post but I’m having the same issue as you 

@Juice75 I changed fuel pump fuel filter plugs and new wires changed tps and it just feels like Im driving up a steep hill 

going up hill is ridiculous i uave to floor it to stay at speed limit 

and same thing if I let off the gas it slows me down as if I’m pressing the breaks any update? Did you ever find a fix?

his fix was a bad cat. He did extensive replacement and his issue was ungoing for a long time.  

  • 1 year later...
Posted

Same exact issue with my 05 XL.. but would that cause handling to be a little rough at times? I'm beginning to think my Yuki has bipolar. Lol. drives fine on one trip, then next trip, everything feels off. Then back to riding normal. Im driving my husband nuts with it. he'll test drive it and says he doesn't feel anything. 

  • Like 1
Posted
21 hours ago, YukiTheYukon said:

Same exact issue with my 05 XL.. but would that cause handling to be a little rough at times? I'm beginning to think my Yuki has bipolar. Lol. drives fine on one trip, then next trip, everything feels off. Then back to riding normal. Im driving my husband nuts with it. he'll test drive it and says he doesn't feel anything. 

 

When was the suspension rebuilt last and what brand of parts were used?  The truck is 17 now, almost old enough to vote!  Rebuilt mine at 13 and she drives like new.

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