Starting problem-ready to pull my hair out

[birminghamwildcat]

97 Rodeo V6 with 5speed manual bought used from freind. Knew there was a starter problem before I bought it but $600 plus a starter well it was a steal. Or so I thought. Ran fine across the county home after we popped the clutch until I got about two miles away from the house and then the motor started lugging on acceleration. I figured it was because it was because the battery was dead from sitting up so long. Charged the battery, replaced the starter, and still wont even click when I turn the key. The positive cable connection to the battery is slightly loose but it was not loose enough to register over 12 volts on the gage. Only things in the cockpit working when the key is turned on is the gages and lights on the dash. No radio, no heat/air, no interior or headlights/taillights. Any ideas?

***************Update 1 2/8/09*****************
New terminal connections. Still not starting with starter. One clutch pop to move to avoid towing and noticed the tach registered zero. Batt meter registered zero after startup but before registered over twelve. I'm thinking it may be the ECU?

[99 Fronty]

Originally Posted by birminghamwildcat

The positive cable connection to the battery is slightly loose

Must be rock-solid tight and clean. The starter needs Volts AND Amps. You have one but not the other.

'99

[amigo-2k]

Pull the battery and the alt and have them load tested...

[Cat Fuzz]

The starter pulls the most power of anything in the vehicle. You can have all sorts of things with enough power to work but not enough power to operate the starter. Check all connections and make sure they are tight and clean. Check your clutch safety switch as well. As a test you can also directly energize the starter by simply using a piece of wire and touch to the big terminal on the starter and the small terminal. That will energize the starter directly. It will also by-pass any safety features that are present so make certain that the truck is out of gear and parking brake engaged.