1970 Ford F100 Stalls At Highway Speed

Asked by Jan 09, 2017 at 09:18 PM about the 1970 Ford F-100

Question type: Maintenance & Repair

I bought a 1970 F100 this week. After two days of
running perfectly on two long trips - morning of day
three started fine and at highway speed of 65
started to lose power as if running out of gas.
Engage clutch and down shift and fine but it would
occur again after a min. By pulling over and letting
truck idle it would go away but then occur again at
full speed. The problem persisted so I eventually
towed balance of trip home. Seems to start fine
every time but struggles to get fuel at highway
speed if given enough time. Thoughts?

2 Answers

74,085

I would change the fuel filter and maybe the fuel pump too if the filter change does not fix it.

1 of 1 people found this helpful.

Initially I thought filter/pump too but Ford dealer confirmed filter and pump are new. They mentioned common issue is a faulty Engine Control Module, which prior owner replaced points w. Truck has a Montgomery Ward ECM, which is 30+ yrs old. I went to NAPA but he couldn't discern proper replacement part - he thought it was an Echlin TP85. He was wrong - truck won't even turn over. I'm not sure how to find correct replacement of ECM or whether I should go back to OEM points and condenser. Another friend who knows old Ford trucks said he thought gas tank was creating vacuum and not allowing fuel to carb... I could test by driving on highway at 65 MPH for a while without gas lid but not sure how safe that is. Thoughts on finding correct ECM replacement or vacuum issue in fuel tanks?

Your Answer

Add photo

Related Questions

  • 1970 Ford F100 Stalls At Highway Speed 2 answers

    I bought a 1970 F100 this week. After two days of running perfectly on two long trips - morning of day three started fine and at highway speed of 65 started to lose power as if running out of gas. ...

    1970 Ford F-100

    -

    Maintenance & Repair

  • 1970 ford f100 brake problem 6 answers

    i am thinking of buying a 1970 ford f100 and its really hard to stop (have to put all my might into it) when i took it for a test drive and i was wondering what it could be before i buy it

    1970 Ford F-100

    -

    Maintenance & Repair

  • 1970 Ford F100 not getting fuel 3 answers

    My 1970 Ford F100 isn't getting fuel. Replaced the carb and it will run for a good few miles then bog out and die. Plenty of gas in it too. Ideas?

    1970 Ford F-100

    -

    Maintenance & Repair

  • f100 stalls in gear 15 answers

    i have an 82 f100 4.9 300 she has vacuum leaks but in idle runs great timing was set to 10 degrees and carb was rebuilt and cleaned by a local carb shop but the truck itself has trouble starting runs ...

    1982 Ford F-100

    -

    Maintenance & Repair

  • where is the fill point for a 3 speed manual transmission 1976 Ford F100? Is it the speedometer hole or is there another fill point? 3 answers

    Where is the fill point for a manual transmission Ford F100 ? Is it the speedometer hole or is there another fill plug? Do I fill it till the fluid runs out of the fill hole?

    1976 Ford F-100

    -

    Maintenance & Repair

Search Ford F-100 Questions

Ford F-100 Experts

#1 tennisshoes
tennisshoes
Reputation 470
#2 MrBlueOval
MrBlueOval
Reputation 310
#3 Rowefast
Rowefast
Reputation 280
View All

Related Models For Sale

Used Ford F-250
4 listings
Used Ford Mustang
9 Great Deals out of 1,204 listings starting at $2,995
Used Ford Bronco
2 listings

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.