Just installed an engine and is running good when it starts. When the engine first starts cranking it is zipping along then all of the sudden the cranking slows dramatically and then all of the sudden it cranks faster until it starts. When it starts, It looks like there is a pretty good amp draw on the amp meter but it is still charging. When I turn on the lights, the amp meter is almost pegged on the low side. But here is the weird deal, when I put a load on it like the lights or something, the oil pressure and water temp gauges peg out on the high side. What the heck is going on? I believe the amp meter a little but I don't believe the water temp and oil pressure guages when an electrical load is applied. I don't get a check engine light either. I also had a spare alternator I tried with the same results.

 

The Cluster has a bad ground.
More than likely it is the body ground under the hood and the body is not grounded very well.