"dead spot" at certain RPM

Discussion in 'Classic Mustang Specific Tech' started by DissFigured, Jul 28, 2007.

  1. Car: 65, auto, 289, FMX

    I was driving down the highway (maybe doing 50 mph), and suddenly, it felt like the car shut off. I hit the gas and it would do nothing and I started to pull on to the shoulder and I realized the car was still running. I barely pressed the gas, and it kept going but was running like it was sort of in between gears just sort of pulsing (hard to describe) It was like it was going in and out between neutral and drive or something like that.

    I managed to get where I was going and back home (about 30 miles round trip) with out it happening again.

    Cruising around the neighborhood at 15 - 20 mph is not a problem but again today, I gunned it and it hit this not so sweet spot again and it started to do the same thing.

    Any thoughts? Where should I start one this one?

    I got an oil change about a week before it happened but I am not sure if there are any mistakes they could have made during that process that would cause this.

    Fuel filter is brand new also.
  2. sounds like you got an ignition problem, or the fuel pump is on its last legs.
  3. New crap:

    twice yesterday, it died while idling, and took 15 minutes to get it started. Cranks like a champ though.

    Could this be a timing issue?

    Also where is my fuel pump located. I haven't done to much work on the engine / ignition so I am sort of weak on knowledge in this area. I really thought I didn't have a fuel pump on a carbonated engine. I thought that was just on EFI.
  4. Just follow your fuel line back from the carb to find the pump. If your still running the old mechanical fuel pump and not an electric one it will be mounted on the driver's side of the engine near the front. If it is your problem it will probably take you all of 5 minutes to change it out.
  5. I found it and I don;t know if it is the problem or not but I will change it and see if my problem stops.

    Are there better ones? You differentiated between electric and manual in your post so I didn't know if this might be a good opportunity to upgrade to something better or if I should just replace it w/ the same model.


    Also, gould any of my symptoms be related to the tranny? I have had some issues w/ it in the past but they seemed to have magically gone away.
  6. Just get you a performance mechanical fuel pump. They can be sourced through a local parts store if your lucky. You may need to get some extra length of fuel line and some clamps just in case the fuel lines dont mate up. Just a good high flow pump will work great.

    Also, pull your distributor cap and make sure it isnt corroded in there. If so, a new cap and rotor will be needed. Those are cheap as well.

    My dad actually lives up in McKinney and could probably fix it for some dough of course. He would fix it right and make sure nothing else is wrong. Just a thought.
  7. :rlaugh: Carbonated ? :rlaugh: First time I heard that one.:rlaugh:
  8. F-ing spell checker changed it on me I guess.

    I should re read my posts before I hit submit.

    Before I go changing the fuel pump, is there anything else that may cause the symptoms I described? (The dist is brand new btw)
  9. Anyone here in the Dallas area? Willing to take a ride w/ me and help diagnose the issue?

    I have a history w/ this car of fixing 6 things before I get to the thing that is actually problematic. I have the ford Manuel for the car and it mentions a couple different things that could be it but I don't want to fix the fuel pump, just to rule it out as the cause and find out that it is something else.

    Working wife just became stay at home mom so $$$ is now a bigger issue than before so I want to be certain.
  10. Have you replaced the inline fuel filter ? If so, how recently ? Also try removing the rubber fuel line between the pump and fender well (input side of the pump) and blow compressed air back thru the line to the tank to make sure it's clear. It's not uncommon to have rust build up in sharp corners of the line and plug it. You don't need a high dollar, high flow pump for your application a stock O.E. pump is plenty. I haven't checked, but these used to retail for $15-20 for rebuilt units.