Replacement motor questions but hopefully fixable

[Fless]

Couldn't an exhaust leak cause a misfire?

 

[89Suburban]

Couldn't an exhaust leak cause a misfire?

 

[wsteele]

Couldn't an exhaust leak cause a misfire?

I have never had an exhaust leak cause a misfire (at least one that leaked at the exhaust manifold). But maybe, I guess depending on the valve timing.

 

[rockdogz]

I checked the exhaust bolts and they seemed tight.
I’m leaning towards pulling it apart to check the lifters/heads/intake

 

[wsteele]

I checked the exhaust bolts and they seemed tight.
I’m leaning towards pulling it apart to check the lifters/heads/intake

Did you verify with an audible test that number 4 injector was firing?

 

[wsteele]

Also, I would do the intake manifold leak test with that CRC intake manifold aerosol stuff. If you have an intake leak, it likely will show up with it.

 

[BobBilly]

So I seem to have a blown (and not blown as in supercharger) up 5.3 in my 2008 Tahoe. It just happened but I think it’s a spun rod. I had been planning to research engine swaps but this came at a bad time so I just want to swap in a remanufactured engine.
should I go for another 5.3 or is there a straightforward swap or kit for something larger (6.0?) or newer? I need something that’s already sorted out and will be smog legal in CA.
Any and all suggestions on someplace that could hook me up would be most appreciated!
Thanks
Tom

 

[BobBilly]

I
have a 2005 Yukon XLT LOADED andwas in good conditio, it was my daughter’s and her husband was going to Trade it in for $2300, with 180,ooo miles. I decided to buy it from him and put a new engine in.
I bought a rebuilt “Long Block”, from Rockauto.com for $1650.00 I put it in my self and then had a rebuilt transmission installed for another $1,650.00. It has been 19 months and I am very pleased to have a like new SUV for much less than buying a new one. Even if you have to pay a shop to put the engine in for you, about $1,000.00, you still come out better than buying a new SUV at the prices today, if you can actually find one.

 

[Rocket Man]

I
have a 2005 Yukon XLT LOADED andwas in good conditio, it was my daughter’s and her husband was going to Trade it in for $2300, with 180,ooo miles. I decided to buy it from him and put a new engine in.
I bought a rebuilt “Long Block”, from Rockauto.com for $1650.00 I put it in my self and then had a rebuilt transmission installed for another $1,650.00. It has been 19 months and I am very pleased to have a like new SUV for much less than buying a new one. Even if you have to pay a shop to put the engine in for you, about $1,000.00, you still come out better than buying a new SUV at the prices today, if you can actually find one.

Why did you put in a new engine? Unless it was badly mistreated it was good for another 200-300,000 miles. 4-500,000 miles isn't uncommon for the LS based engines.

 

[TollKeeper]

Can we back up a minute?

I understand you swapped coils, but did you verify spark was actually going across the strap at the spark plug?

Other than a collapsed lifter, you have ruled out pretty much everything else. So now it's a matter of verifying the result.