2003 6.0 Silverado missing and sputtering under load

[rgv]

My work/hunting truck is a 2003 2500HD with a 6.0L and a 5 speed manual. All stock.

 

It has 111,000 km (69,000 miles) on it currently and runs perfect except it hesitates/misses/chugs/sputters under load between 1500 and 2200 rpm

 

you can make it do it on demand with the empty truck and it is much more pronounced with a load.

 

No error codes, the MAF is clean, fresh plugs, new fuel pump and filter, TPS tracks properly on a scantool, MAF looks normal on scantool (no apparent vacuum leak), no KR showing on scantool......

 

Truck gets normal fuel economy and makes good power otherwise.

 

Any ideas greatly appreciated!

[beetle]

My old 2005 4.8 had the exact same symptoms, turned out to be bad plug wires....there were no codes either.

[brainpause]

Is the replacements fuel pump aftermarket, or GM/Delco?

 

I would also check fuel pressure. Maybe you got a bad replacement pump.

[asc08]

Clogged Cats?

[markw8]

Check the fuel pressure.

 

Mark

[brainpause]

Any news?