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Rough Idle, can't hold rpms

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    #1

    Rough Idle, can't hold rpms

    I took starter fluid and checked everywhere for vacuum leaks. I've got new gaskets on the upper and lower and throttle body. previous owner already did the mess under the intake clean up but I went in and replaced those hoses anyway. if I try and hold the rpms at anything above idle, after a few seconds they will drop and the engine almost stalls. injectors aren't leaking and my only other guess would be something fuel related? I bought new mustang injectors so maybe it's the fuel regulator or something?

    before all this it was running but had a fuel leak from what I believed to be the two short hoses under the intake manifold but after trying the old injectors again it leaked around one of them so that oring mustve been bad. so with that info when the new injectors are in and not leaking I'm down to icv or fuel pressure regulator/something fuel system related



    I also at one point got the 1262 code for the icv, but it's now back to 1444

    before doing this I also changed the valve cover gasket but I don't think it's related afaik


    sorry for the long winded paragraphs just trying to provide as much info as possible to try and solve this quickly
    Tags: None
    #2
    does it drive otherwise?

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      #3
      haven't moved it out of the garage, been working on various things on it for a few months. I would guess it wouldn't since I can't make it hold a constant rpm on throttle before it starts choking

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        #4
        If it runs fine at or near WOT try a different TPS and an O2 sensor if the stall occurs only when up to temp.

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          #5
          Originally posted by roguetoaster View Post
          If it runs fine at or near WOT try a different TPS and an O2 sensor if the stall occurs only when up to temp.
          would it still be this if its at every temp and cant hold WOT? haha trying to minimize parts throwing

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            #6
            At this point you're just looking to trouble shoot. It could be: CPS, AFM, ground connection, or the coil. The o2 probably wouldn't hurt it that much, but you can always test that by just unplugging the o2 and seeing if any difference is made. The stock software should run stock injectors on a stock car pretty well without any o2 feedback. Well enough to see if that was your problem at least.

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              #7
              could it maybe be water in the gas tank? we did have a pretty large change in temperature this weekend

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                #8
                Are you losing any fuel when not driving the car? Gas evaporates pretty quickly, so if you did have a hole in your tank, you'd definitely be noticing fuel going missing.

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                  #9
                  all the fuel leaks that I know of are fixed and no leaks. I've only got about 1/4 of a tank in it

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                    #10
                    Originally posted by Sladek View Post
                    would it still be this if its at every temp and cant hold WOT? haha trying to minimize parts throwing
                    Yeah, I was just thinking that the car thought you were at WOT for some reason any time off of idle, and enriched the heck out the mixture without air flow to compensate. Granted, this shouldn't happen when the AFM disagrees.

                    What's the exhaust smell like when running?

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                      #11
                      Originally posted by roguetoaster View Post
                      Yeah, I was just thinking that the car thought you were at WOT for some reason any time off of idle, and enriched the heck out the mixture without air flow to compensate. Granted, this shouldn't happen when the AFM disagrees.

                      What's the exhaust smell like when running?


                      it smells pretty rich of something but it also has no cat thanks to the PO. I'm assuming it's got to be something under the hood since that's all I've messed with since I started it last and it ran like a champ

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                        #12
                        Rough Idle, can't hold rpms

                        no luck with the ICV replaced. still the same thing as it seems like it runs out of gas if I try and rev it up and hold the rpms. haven't had a chance to check fuel pressure yet

                        and it still sounds lopey and starts to try and stall

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                          #13
                          so I changed back to the original injectors and that helped a little bit over the mustang injectors. i still have a lumpy idle.

                          I hooked up a fuel pressure gauge and took a video. anyone have any thoughts?
                          VimeUhOh
                          https://vimeo.com/184134578
                          Sorry, we couldn’t find that page

                          Comment

                            #14
                            I tried taking it around the block. got out of the garage and it fell on its face. had extreme hesitation and eventually just stalled not 50 ft from the garage. the spec for fuel pressure is 43psi and idling I'm low. anybody? bueller?

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                              #15
                              The idle sounds almost like timing is off
                              but the rest of the issues sound like bad AFM.
                              try disconnecting the AFM and see if anything changes.

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