Power Loss - help appreciated.

[Bluec10]

My 2006 Sierra w. 4.8 is suddenly using power. At highway speed the truck will suddenly lose power - the tach will drop to zero then quickly bounce back up again. This only happens when the truck has been driven for a while. It often does this several times in a row, creating kind of a stuttering. At first this only happened at high RPM but now it happens across the range.

[txab]

One thing.....check fuel pump pressure and flow rate.

 

Pump pressure. Check key on , engine off

[Bluec10]

My 2005 Sierra w. 4.8 is suddenly losing power. At highway speed the truck will suddenly lose power - the tach will drop to zero then quickly bounce back up again. This only happens when the truck has been driven for a while and is warm. It often does this several times in a row, creating kind of a stuttering. At first this only happened at high RPM but now it happens across the range.

 

At first I thought dirty fuel filter, but it doesn't have a fuel filter. Check engine isn't on.

 

Any ideas?

[txab]

Did you do any of things suggested in this thread over a month ago?