rpm tach acting weird after mods

[GreenStreak]

My tach use to work perfectly and then I decided to tear my car apart and add: fp green w/external gate, 3" open down pipe for now, a SBR coil on plug, 680 injectors, Bushur CAI, SBR FMIC, MAFT w/3" gm mas, walbro 255, I'm working on putting on the fpr right now, and a dsmlink. Well that's all I can think of at the top of my head.
After sitting in my car trying to tune some things at idle, I noticed that my dsmlink rpm reading and my tach rpm reading are way off. At idle my tach reads at 500 rpm. When I rev it up to 2500rpm on the dsmlink, my tach only reads 1800-1900 rpm. Did I forget to do something that I'm not aware of or does this usually happen with extensive mods? Has anyone experienced this before?

 

[talon_boy69]

If you connected the rpm wire from the maft to the CAS signal wire with the supplied clip, probably it has splitted the wire...the black one...try checking that...just for people to know...when I installed the ssautochrome "header" ...it produced some strange vibration or resonance point that made the tach act weird...after the header cracked, I decided to go evo manny and pte...problem solved...