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I have a Cobra replica with all Mustang running gear: diff, spindles, rack, engine, trans, computer, etc......
The reason I came here is that you have a technical forum for 5.0s. The other forums I'm on don't discuss engine stuff exclusively. Sometimes, you get decent advice but not consistent. Now that mine is running and I have app 1K on it, I want to tune and discover ways to improve the performance.
My 5.0 is mildly modified: Holley Systemax EFI, 24 lb injectors/MAF, 75mm throttle body, GT40p heads (ported), E cam, BBK 4x4 headers to side pipes, Crane rocker rollers, cold air system to fender well, alum fly wheel. The PCM is from a 92 GT.
My question is: what will cause an intermittent surge +/- 1K rpms? I just replaced upper intake gasket and throttle body gaskets and checked for vacuum leaks. At times, it idles perfectly and lopes like it should. This is my first experience with a FSB and EFI so I am thinking that I may have a computer issue but the problem is on and off so it's hard to get a handle on it.
Thanks in advance,
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