I just got a 1979 toyota stardust, it had been sitting for awhile, wasn't running right when i got it. When i get it out on the freeway it will run down the road at a nice 60 to 65 for about 5-7 miles. Then i start to lose speed, acts like i am running out of gas. This happened right after i got it up and running. At that time, i replaced the fuel filter. I put on an aftermarket one that is clear. ( i like to see what's going on lol) The first time it happened the filter was plugged up you could see it. I then put 3 bottles of b-12, a bottle of heat and some marvel mystery oil in the gas. Let it sit for a couple of days. Went out replaced the cartrage in the filter, ran it for about 2 hours....ran great....nothing in the filter...looked clean and was full of gas. I thought cool, i have it fixed. Drove it around town all day doing my erands....ran great no probs. Drove it to work.....np...drove it home on the freeway....went 65 all the way (about 12 miles)....seemed to have good power. Put new shocks on it yesterday...thought i would drive it to work again and check out the "new" ride feel. Got on the freeway....it was running great...about 5-7 miles in to the trip...it starts cutting out again....got out quick looked at the filter....looks clean and it's full of fuel. revved up the motor while sitting there with the hood open...filter stayed full but the motor started acting like it wasn't getting gas again. one more note.....if when it starts to cut out...i let off the gas and let it idle (which it does sorta)....wait for about 20 to 40 sec i can get it to run for about another 100 feet. I know this cause this is how i made it the last 3 miles into work this morning...lol Anyone have any ideas of what to look at next???