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Rough idle 2008 and 2011

6K views 6 replies 6 participants last post by  Pak713 
#1 ·
Hello all, Im new to the site i just bought an 08 silverado with the 5.3, 48,000 miles and it has a rough idle sort of like a bad plug, the funny thing is my brother bought a brand new one and it has the same problem, anyone have any ideas? im goin to schedule an appointment with the dealer next week after my vacation, was just wondering if anyone has any input... ty Tim
 
#2 ·
I've had similar issues with my 2010 LT 4x4 Z71 since new. I took it back to the dealer the week after I bought it they said nothing wrong. Now I have 20k miles and it does it all the time when warmed up, but especially when I'm forced to go slow off the line and it shifts into 3rd at like 20, then it misses and does this chug a chug thing until I get up to about 30 MPH.

Regards,
Jeff
 
#4 ·
2011 bought with 85k on and runs great. Just started have a funky idle issue too. Same at park/neutral/drive at idle (600 rpm). Step on the
gas and it takes off fine and runs smooth. Does not show an error on scanner nor does it throw a check engine light. Feels like a miss but I would
think it would show on the scanner. Any thoughts appreciated.
 
#5 ·
To the OP depends on what you calling a rough idle. How much fluctuation on the tach. Gm 5.3's are known to have a stumble on idle in drive and park. That is normal. That's why most of us or at least me, when we get a custom tune bump up the idle in drive and idle in park up a little to smooth it out. Every GM truck I've ever owned has had the stumble at idle. But if it's really bad I would definitely clean the throttle body. On the normal stumble you should barely see the tach gauge move but definitely feel it. I'm sure some other members will chime in here. But that's been my experience.
 
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