Me and my friend just put an LS into his auto sedan and did an mpfi conversion and manual conversion. We used obd0 injectors w/resistor box. We initially had a problem getting the fuel pump to turn on, couldn't figure out why so eventually we just ran a switch directly to the battery allowing us to manually power it on and off when car is in or not in use. Worked great car runs awesome no problems at all.

That is until our first semi-long trip on the way to pay some tickets, we started to run out of gas, we figured ah w.e we changed the cluster so maybe the gas gauge was either off or broken, got some gas, problem solved. On the way home we stopped at my house to drop me off and he went home. Talked to him today and he said he stopped and threw in 10$ in gas just to be safe then went home and didn't go anywhere else till today and the same thing happened he was low on gas? He only lives about a mile away from my house right in town. We always make sure the pump is turned off when turning the car off. Does anybody have any idea what the problem could be?

Also here are the symptoms of the problem, assuming it is what we think and it truly is loosing gas (problem goes away when adding gas)

-sputters when gassing.
-Sputters at high rpms.
-stalls at lights.

Like i said, when we get gas it goes away.

My only thoughts are if the gas tank was initially dry enough that we were loosing gas, the first 10$ we threw in was really nothing especially since that's only 2 gallons of gas and we still were only on the way to the court house so we went there and then came back and then he went home. Court is about 30 miles away from us. Then the second 10$ he put in after, he could have been already close to running out for the second time and maybe he drove around a little bit today before telling me what happened, he is sort of an idiot.

EDIT: car won't move now, 20$ added in. Could the injectors have went? we did get them from a junkyard.

 

not sure but i know my gas gauge will read empty with 4 gallons left

 

Yeah i thought something like that at first, but this is way to fast.

 

If you run it that low all the time, the pump could be getting warm and not pumping enough gas to keep 'er running well. When was the last time the filter was changed as well?

 

it's been a while, and he is known for running on empty all the time. could very well be the issue.

 

Car won't go anywhere now, did the injectors go?

EDIT: probably the filter. changing and updating for google search purposes.