hesitating on 1/4 tank

[xlboy]

i just picked up my 1971 911s from 4 months in the shop where the tranny and diff were rebuilt as well as a bunch of other odds and ends. when the work was completed the mechanic who did the work test drove it several times, the owner of the shop test drove it and i test drove it around the shop for a while before i headed home with it.

as i started home the gas gauge read about 1/4. in the past the gauge has been fairly accurate and i've driven it till the warning light comes on many times and promptly filled the tank with approximately 14 gallons.

on the way home i started noticing the engine hesitating above 3500 rpms and whenever i would accelerate hard. on the highway it would also hesitate and buck a little and then continue on for 30 seconds and it would happen again. it felt a little like the car was running out of gas but then it would keep running so i thought it might be a fuel injector issue.

just to eliminate the possibility of very low fuel i stopped for gas before i was going to return to the shop. the car took 10 gallons and then ran perfectly the rest of the day.

anybody know why this would happen when the tank is low but not real low? im not familiar with how the fuel is picked up in the tank but im guessing that may be the issue.

[pwd72s]

John, back before MFI fuel filters cost $60, I'd have suggested you cut yours open, see what you find. Just guessing here, but I suspect krud or H20 in your gas...likely H20 since it settles to the bottom. Tank draining may be in order? If not 100% sure of the procedure, keeping safety in mind above all, you may wish to go to the pros for this service...

[Wolf Knierim]

The fuel pickup sits in small well at the very bottom of the tank, so it is possible for the complete contents of the tank to be consumed. There is a small brass strainer screen on the the pickup line inside the tank. Your car had been sitting awhile with a low fuel level, I would also suspect water first.
Wolfgang

[pwd72s]

The fuel pickup sits in small well at the very bottom of the tank, so it is possible for the complete contents of the tank to be consumed. There is a small brass strainer screen on the the pickup line inside the tank. Your car had been sitting awhile with a low fuel level, I would also suspect water first.
Wolfgang

Wolf? I couldn't agree more. Your guess on how much H20? Sadly, it doesn't take much...but then, it could easily be other "crud" clogging the screen. That's why I suggested cutting the filter. But with filters costing 60 bucks a pop, maybe it would be cheaper to drain the tank and check the screen first, assuming one did the chore himself???