Small block idles rough only when in gear

Mopar Performance Issues

  1. nitronut

    nitronut Well-Known Member

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    Found it! The cap on the rear intake vacuum port was cracked. Replaced it and fixed the problem. Thank You! I have a mildly built small block 360 which idles very rough when put in gear. (idles smooth in park). Only recent changes to the motor was I adjusted / took out some slack on the throttle cable. Starts quickly when hot and have to crank a few seconds when cold which is normal for the engine. Checked all the carb's vacuum plugs, spark plug wires, etc. Has me totally baffled. Would taking a little slack out of the throttle cable cause this?
     
    Last edited: Aug 21, 2021
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    • 69FBCuda

      69FBCuda I'm so confused! FABO Gold Member

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      Put a vacuum gage on it.
      Post pictures of your motor setup
       
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      • pishta

        pishta I know I'm right....

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        I bet your A/F is wrong. I battled that for about 3 months and a turn of the screw fixed it. Cant remember if it was rich or lean...make sure the advance plate in the distributor is greased too. Found mine (340 dual point) to be gunked with hard grease limiting its return speed and position. check your timing in gear .
         
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        • rumblefish360

          rumblefish360 So close, yet so far away FABO Gold Member

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          You might have moved the throttle blade position slightly when you took out the slack. Since it was the only change done, the effect has to be directly connected.
          Also look at the carb itself on the outside to see if you bumped any linkage around.
           
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          • fishmens67

            fishmens67 FABO Gold Member FABO Gold Member

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            Make sure throttle cable is returning to idle.
            I set my timing and idle mixture in gear.
             
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            • nitronut

              nitronut Well-Known Member

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              Found it! Thank you. The vacuum port cap on the rear of the intake was cracked. Put a new one on and fixed it. What a huge relief. Thanks again!
               
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              • nitronut

                nitronut Well-Known Member

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                Found it! The cap on the back of the intake vacuum port was cracked...Thank you!
                 
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                • nitronut

                  nitronut Well-Known Member

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                  Found it! The cap on the rear vacuum port of the intake was cracked. Put on a new one and fixed it. Thank you!
                   
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                  • nitronut

                    nitronut Well-Known Member

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                    Found it! A cracked cap on the intake rear vacuum port was cracked. Replaced it and fixed the issue. Thank you!
                     
                  • nitronut

                    nitronut Well-Known Member

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                    Found it! A cracked cap on the rear intake port was bad. Replaced and all is well. Thank you!
                     
                  • pishta

                    pishta I know I'm right....

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                    So you were lean....check! :thumbsup:
                     
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                    • AJ/FormS

                      AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                      Is there an echo in here?
                      Hello ........ elloooo ............llooo ............loo ............oo ..........o
                       
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                      • nitronut

                        nitronut Well-Known Member

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                        lol... sorry I thought I had to respond to each reply.
                         
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                        • rumblefish360

                          rumblefish360 So close, yet so far away FABO Gold Member

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                          :rofl::rofl::rofl::rofl::rofl:
                           
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                          • Ricks70Duster340

                            Ricks70Duster340 Child of the King, widower FABO Gold Member

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                            Maybe *you* were running lean...!
                             
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                            • nitronut

                              nitronut Well-Known Member

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                              :rofl:LOL... probably so!
                               
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                              • rumblefish360

                                rumblefish360 So close, yet so far away FABO Gold Member

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                                It happens you know
                                 
                              • DrCharles

                                DrCharles Well-Known Member

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                                Have you considered looking for a cracked vacuum cap? :lol:
                                 
                              • nitronut

                                nitronut Well-Known Member

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                                lol I will now!
                                 
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