Questions and Answers
The Weirdest Thing...
Q. I have a 1996 Mustang GT 4.6 V-8 5 speed with 90,000 miles on it. Since 88,000 miles my car has been doing the weirdest thing. When I am driving down a road with dips in it, my RPM's will bounce around with the car. For example: I am approaching a dip in the road so I press in the clutch pedal and the RPM's linger around 2,000 RPM.
When I hit the bottom of the dip the RPM's slam down to 100 RPM and then when the road smooths out the RPM's fly back up to 2,000 RPM and some times past it to 3,000 RPM. It's like the RPM's bounce with force put on the car. I have no Idea what would cause this. I have had some people tell me it could be vacuum related and some say it could just be a bad fuel filter.
Thanks for you time,
MattA. It sounds like you have a loose connection somewhere and hitting dips and bumps shake it up. This is why Ford developed their world famous "wiggle" test. The wiggle test means that you grab harnesses and connectors and shake them until the problems appears. Then you know you are in the general area of the problem.
I would check each vacuum line and make sure the are in good shape and connected properly. Then I would check each connector and make sure they are clean and tight. I have several styles of male pin connectors and I insert one into each of the matching female connectors to make sure each one is tight. If I find a loose one I use a small screwdriver to tighten it up.
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