tach not running right

[Tx-Sx-FS]

i just put in some glow gauges last night and when i started the car today, the tach wouldnt go up. While driving and really geting on it, the needle would go up and then stick...what could it be? also i popped my hood, pushed the throtle cable and when i released it i heard like air being released from something...it comes from the intake manifold/injectors area...what is that from?