Ok guys what to do, what to do, when i start my truck the tach shoots up to 2000rpm and stays there all through the driving range and idle, what could possibly cause that???And 2 should I just put in an aftermarket tach? if so do you splice it in to the tach wire off the coil, then ground it...

92 f150 2wd 5.8l no mods exhaust suck, while driving and put it in passing gear or climbing up a little hill it tends to chug, the egr went bad on me so I unplugged it, it ran fine after that,I replaced the fuel filter the plugs and wires cap and rotor are not even a year old, I do have a bad...