'78 Westy

My boyfriend and I purchased a '78 Volkswagen Westfalia about a year ago. It had one owner before us, and was serviced regularly - it ran great for the first few months of ownership. Since then, it has had some minor issues, but one in particular is becoming a major problem. It began to stall intermittently a few months back, so we took it into a “bus shop” to be serviced. We were informed that the fuel collar had disintegrated into the fuel tank - the easy ($300) fix was to go in and extract the large chunks out that appeared to be clogging the gas lines. After the fix, it appeared to be running great, until a few days later. To avoid paying another large chunk of money, we decided to take the matter into our own hands. My boyfriend changed the fuel filter, and re-filtered the fuel with a non-contact vacuum pump, but that did not solve the problem. It appears to run fine after it sits for a few days, but after running for a while, it begins to stall when we brake or when idling for more than 30 seconds. The idle is also quite rough. After doing some reading, our next idea is to replace the temp sensor 2 as a possible fix, or dropping the engine to pull out the gas tank. Is there anything you suggest?

Cheers,
Bree + Matt + '78 Westy