Tachometer PROBLEM!!!!

[95splashranger]

hi i just got my truck and it has a tach problem. when i go and start the truck up the tach wont work.But if i push in the clutch it will work.Also if i am in netural and press the brakes hard it will work. also if i slam the hood hard it will flicker. but right when i let off the brake or clutch it will go back down to zero. whats my problem? thanks

 

[tripplec]

Clearly you have already isolated the problem to your peddles. Looking around under the dash for wires rubbing (shorting out) near either peddal. Since the brake mechanism goes directly into the booster box on the other side of the firewall. I cannot see it being an under the hood issue but underneath the dash.