can I add an inline fuel pump instead of replacing the pump in the tank?

It would be easier and cheaper to add an inline pump. Does anyone know if that would work?  

Most newer cars require more pressure than the average inline fuel pump can deliver. Also finding a safe place to mount the pump isnt usually all that easy.
Pricewise since I don't know what your car is would be impossible to guess but in most cases there wouldn't be enough difference to warrant the extra work with wiring and mounting an external pump. 

It is a 99 suburban with the 42 gallon tank. Finding a safe place for the pump would not be a problem but I don't know about the pressure needed.

It WILL NOT be cheaper to go inline. Theres custom modification that would have to be done, and that costs $$$. 
 
You'll need the greater pressures with the 5.7L.   If you externalize the fuel pump and get a high pressure fuel pump, it will work with custom modifications to the tank, but the noise will drive you nuts.
 

Do you know what the "custom modifications" are. I can get a high pressure pump for $100 that alot cheaper than a good intank pump. 

I don't understand. If an inline pump is 100$ and you have to make it mount and hook up how much are they trying to rape you for the original equipment pump?
In October I put a new pump into a 99 3/4 ton 4x4  pick up. The pump was $54 and I bought the filter sock with it for $9 plus tax still was a long ways from $100.
They put the pumps in the tank now for safety reasons (not enough oxygen inside the tank for fire or explosion) I think I would stick with it myself.

I put a new $160 pump in the tank two years ago. If I had bought the $300 one I probably would not have this problem. I put it in myself took about 4 hours and it was a pain in the as. If anyone has cheaper and easy way to do this I would be happy to here it. Thanks 

  I remember the first time I did an in tank fuel pump on my truck, on the floor and countless hours.  The next time it went out, I cut a hole in the floor of the bed and rtv-ed a patch down afterwards (have a carpet bedliner over).  Now it can be done in ten minutes and no more rust in the eyes.   

It was noisy wasn't it?

Do you plan on deleting the oem pump?  since you are going to be there you may as well just replace it.  What is the cause for the replacement anyways?  2 years is too often to replace a pump.  In addition to an inline pump you will need a fuel preassure regulator.

I don't know why the pump didn't last. Cutting the whole sounds good. I wonder if it could be done while the tank is in place? 

 Absolutely, I put a welding blanket over the tank and used a cut-off wheel by 3M.  It was too expensive for a hole saw that big.  Make sure there's nothing in the way (fuel/brake lines, wire, reinforcements welded to the floor) before starting.

cutting what hole?  Or are you refering to deleting the pump?

 In the floor of the vehicle to access the stock in-tank pump from the top.  I covered the hole with a larger piece of metal and some RTV.  If not properly equipt, it may be best to have a local bodyshop do it, I'm sure you're farmiliar with all the lawyer blurb.