the problem is a bad connection. there is a connection that runs along the driver side kick panel. try kicking right below the foot rest (in that area). mines been doing that since i got it (3yrs). i give it a swift kick and it goes away for awhile.
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94gt incon tt _ 11.66@124
455rwhp/476rwtq
68 stang 351w _ 12.99@106
my stangs