Announcement

Collapse
No announcement yet.

Hesitation on start up and acceleration

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

    Hesitation on start up and acceleration

    Over the past few weeks my mustang has been acting weird - it used to always burst into life when starting with a glorious roar but recently its been sounding very lethargic and lumpy on start up (cold start ups). It is also very hesitant on acceleration and feels as though there is something holding it back stopping it from being allowed to rev - its a very odd feeling when driving it? It sounds normal i.e.doesn't sound like its mis-firing or running on a few less cylinders etc.

    Any ideas from anyone what it could be? I could take it down to my local Ford dealer but I know they wont have a clue. Thanks.

    #2
    What modifications have been done to the car ?
    if the problem is constant and there have been no real mechanical changes I would get it into a Ford Dealer for a diagnostic check.
    its hard to say without knowing if anything has changed. It is not something I have heard of before, so it’s not an obvious or common problem.
    regards
    Mark

    Webmaster - Mustang Owners Club of Great Britain.
    1994 - Indy Pace Car 938/1000
    1995 - Cobra R 61/250

    Comment


      #3
      Could be a vacuum leak, check to see if any hoses/pipes have come adrift.
      1967 White Convertible Auto ...... 1994 to 2004
      2005 Redfire GT Manual......2008 to 2010
      2010 Kona Blue GT Auto ...... 2010 to 2013


      MOCGB #332 since 1994

      Comment


        #4
        Many thanks for the responses however wouldn't the engine management light come on if there were any faults present? The car doesn't have any engine mods at all.

        Comment


          #5
          I'm no expert on mustangs at all but I know that most cars nowadays will run poorly with a vacuum leak but not necessarily throw an engine management light. First things to check are the seals on the oil cap and dipstick makes sure they're on properly, then have a look around at any breather/pcv/hose connectors loose. You may hear a whistle from a minor leak. You could also monitor your afr using the gauge and see if that is showing anything significant. My gt likes to hover around 14:1 on tick over and mostly maintains this during all acceleration.

          Comment


            #6
            It's an S550 Mustang with no modifications, so the best place to go is Ford, and get them to troubleshoot it. Is it still covered under warranty ?

            Webmaster - Mustang Owners Club of Great Britain.
            1994 - Indy Pace Car 938/1000
            1995 - Cobra R 61/250

            Comment


              #7
              I really dont want to take it to Ford if I can help it as ive taken to both of the ones local to me in the past and had very bad experiences of both.

              I have checked the vac pressure and having run the car for about 5 mins following a cold start up, it stayed consistent at 19 - does that mean its leaking somewhere or is that normal?

              Comment


                #8
                A big one use to be the gas cap not being on tight enough, You were told to close it for several clicks, I have no idea why but this was one that was mentioned quite a lot a few years ago.
                Please visit our Classic Mustang for sale site: www.classicamericancarsales.co.uk
                We stock a large selection of freshly imported Classic 1960s Mustangs. Fastbacks, Convertibles and Coupes. Cars are in stock in the Southeast of England with more shipping from the USA at all times. Other interesting American cars also stocked. CSRP disk brake setups sold

                Comment


                  #9
                  I kept the vac gauge on whilst driving it yesterday and the vac pressure dropped to 0 under hard acceleration and 7 under light acceleration but stayed at around 19 / 20 whilst coasting - is this all normal?

                  Comment


                    #10
                    Is the car under warranty ? I really don't get why (if it's RHD and under warranty) you are not taking this issue to a Ford Dealer.
                    They have FAR more access to Technical information, than this forum does.
                    You are missing the input from probably the most informed information source.
                    If you bought it new, and it has this issue, you have a lot of clout with Ford Motor Company, so use it to your advantage.

                    Webmaster - Mustang Owners Club of Great Britain.
                    1994 - Indy Pace Car 938/1000
                    1995 - Cobra R 61/250

                    Comment


                      #11
                      The car is only 18 months old so still under warranty but as advised, I have had a bad experience there before when they had my car however I have still called them to ask if they can look at it and they have no availability until the 4th April. I cant wait that long so if its a simple problem that I can fix myself or at an independent garage this would be preferable hence asking for help and advice on here that's all.

                      Comment


                        #12
                        Isn't there another dealership within travelling distance you could take it to? Plenty of them.
                        1967 White Convertible Auto ...... 1994 to 2004
                        2005 Redfire GT Manual......2008 to 2010
                        2010 Kona Blue GT Auto ...... 2010 to 2013


                        MOCGB #332 since 1994

                        Comment


                          #13
                          I had those symptoms on my 2005 and it was the fuel pump (albeit an aftermarket piggyback setup). Has the filter been changed?
                          You are probably better getting and OBD 2 reader as that will probably tell you the problem. Mine flagged fuel pressure issues.

                          Comment


                            #14
                            Where bout are you, we have a very good ford dealer near us in Essex and have always treated us with the highest respect although not a ford store they have always been brilliant when it comes to my mustang and wife’s rs both mk2 and mk3 and because they not a part of what I call robot franchise like lookers, allens you get treated like a value customer not just another number. And to top it off they treat your pride and joy the correct way. If you type on google “rates ford grays” you see they come up. Hope you get it sorted soon.

                            Comment


                              #15
                              Originally posted by NSP View Post
                              I kept the vac gauge on whilst driving it yesterday and the vac pressure dropped to 0 under hard acceleration and 7 under light acceleration but stayed at around 19 / 20 whilst coasting - is this all normal?
                              Out for a drive yesterday in my S550 2017 MY. Thought I would check the vac gauge for you. Under acceleration it showed 3 or 4. At a cruise it settled at about 15. And coasting it showed around 20. So not too different from your readings. And I have no issues with hesitation.

                              No idea what the numbers mean but yours seem normal - on my very small sample.

                              Get the car to a dealer for assessment and rectification under warranty I would suggest.

                              Comment

                              Working...
                              X