Nissan Repair: 2001 g20, fuel tank cap, volume test

Question
I have raw gas smell coming from the back of my car forward. It is very strong and happens most frequently when driving the freeway or on a long trip through town, gas quantity does not matter. On occation I get a sudden momentary loss of power when peddal is pressed down. The check engine light is on, I have had it in the shop 4 times now.  All filters have been changed, a clamp on the fuel line that runs on top of the fuel tank has been replaced and all EVP items have been checked or replaced. The light is reset and within a day or to it comes back on.  I am tired of having things replaced and nothing working. I would love any suggestions you might have that I can pass on when I drop it off for the 5th time tomorrow.
Cheers, Liz

Answer
Hi Liz -
Sorry for the late answer. You have probably dropped off your vehicle already.

Has anyone checked the fuel tank cap? This has caused many a problem. If you cannot get a tight seal, it should be replaced.

Another suggestion is to take a fuel pump pressure and volume test.

Other than that, I cannot think of anything, as I am assuming that all basic things have been looked at (fuel filter, leaking fuel line, etc).

Hope this helps Liz -
aloha
calvin