miss fire at 3500 rpm

[saturntech]

I have a bad miss under heavy load, it has the 5.3ltr. It only happens at 3500 rpm and higher, and its only on #2.replaced spark plugs, ignition module, wires, intake gasket. This is stumping me big time, now leaning towards a weak valve spring now ?? any help on this on would be much appreciated

[saturntech]

So since no one has any ides for me I will reply to my own question. So I ended up pulling the head, right bank, sent it out to the machine shop to get valves done, the guy told me that the exhaust valves were leaking but prob not bad enough to cause my miss, he also told me that the valves were moving freely in the guides. He fixed the leaky valves and sent it back to me. So I checked all the lifters, cam lobes, and push rods, all good. So I put everything back together hoping for the best, but problem still there.

[saturntech]

Originally Posted by saturntech

I have a bad miss under heavy load, it has the 5.3ltr. It only happens at 3500 rpm and higher, and its only on #2.replaced spark plugs, ignition module, wires, intake gasket. This is stumping me big time, now leaning towards a weak valve spring now ?? any help on this on would be much appreciated

also replaced #2 injector