# 6.0 l Low Idile Sputtering and Stalling



## red dog (Nov 12, 2011)

As title states 2003 GMC HD automatic stalling when put in drive and strain goes on motor.Also idling low and sputtering in park and drive when stopped.Truck has new plugs,wires,fuel filter,fuel pump.Was giving code of random misfire and had new coils for 4 cylinders replaced.The fuel in truck is new and has had injector cleaners ran threw with the new fuel. Have heard it could be a dirty MAF issue.What is the best way of cleaning this and throttle body?What else could be the cause of this stalling issue?


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## Philbilly2 (Aug 25, 2007)

red dog;2103017 said:


> As title states 2003 GMC HD automatic stalling when put in drive and strain goes on motor.Also idling low and sputtering in park and drive when stopped.Truck has new plugs,wires,fuel filter,fuel pump.Was giving code of random misfire and had new coils for 4 cylinders replaced.The fuel in truck is new and has had injector cleaners ran threw with the new fuel. Have heard it could be a dirty MAF issue.What is the best way of cleaning this and throttle body?What else could be the cause of this stalling issue?


I know this sounds stupid, but is your mass air sensor plugged in/ clean? Those little [email protected] have caused me some head scratching threw they years.


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## chachi1984 (Feb 10, 2012)

had the same problem with an 2002 sierra 2500hd
the EGR valve had carbon build up


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## schrader (Dec 4, 2005)

Why only four coils replaced? Sounds like a bad coil to me.


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## chevboy167 (Dec 7, 2011)

Try tightening down the intake plenum bolts. See if gets better. If does, replace intake gaskets. Has happened on both my 4.8 and 6.0. When temps where colder, the worse the problem. If that is the cause, replace both knock sensors, the wire harness and the oil pressure sending unit all at the same time. Well worth it! Also a MAF sensor may be just enough out of spec to cause these issues but will not throw a code. Happened on my 6.0.


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## Randall Ave (Oct 29, 2014)

Take the maf out, take it apart. Very carefully look at the little sensors. They should look clean. If not get some dedicated cleaner at the auto parts store and clean them. Mine had what looked like hair on one side. Made a huge difference.


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## PLOWMAN45 (Jul 2, 2003)

have you ever run seafoam to clean your truck out they have great you tube video


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## Grantski (Jan 26, 2015)

I was chasing a similar issue w my f250. Seemed to have stopped after a new ignition coil / coil pack (idk if that's the same thing)


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