It sounds like the band for the gear is slipping but you never know, do the little things like mentioned above to see. If all else fails put in a T-5 and it will be more fun to drive, lighter, faster, and better on gas.
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2003 REDFIRE COBRA #3938 of 5082 @ 05/27/2003 1 of 414
MGW Shifter, Stingers, JLT, SS Inserts, MM FLSFC & CC Plates, SS Lines, H&R Race springs, IRS Brace, MRT Hood Struts
ME.com Member #29 - 400rwhp/380rwtq