2002 Blazer Battery/Oil Pressure Sensor Connection?

I have a 2002 Chevy Blazer, V6, roughly 76,000 miles. For about 5 months now, I have noticed when my truck (http://www.2carpros.com/forum/2002-blazer-battery-oil-pressure-sensor-connection-vt58742.html#) is in idle, the oil pressure sensor JUMPS up and down, but not all the way to the high/low extremes (sometimes very quickly and sharp, other times more slowly - it really depends on how long you have been driving). The truck also runs pretty rough while sitting in idle. Along the same lines, whether the truck is idle or in motion, the dome and dash lights flicker - all the time. Over these past 5 months, these problems have been getting worse. However, just last night my 'Service Engine Soon' light went on. Do you think there is a connection between the battery and the oil sensor? I am always up to date on oil changes and check the oil level constantly. Other than when in idle, the truck runs fine.

The lights flickering could be a voltage regulator problem, (The regulator is inside the alternator). It may be related to the oil gauge fluctuation also.

What DTC's, (Diagnostic Trouble Codes) are stored? Idling rough might be a leaking fuel injector or leaking fuel pressure regulator allowing excess fuel into the crankcase. This would thin the oil and could also cause the oil pressure gauge to fluctuate.

I haven't looked into why the engine light came on yet, but I should have the code(s) for the issue tomorrow.

If there is a voltage regulator problem, what exactly does that require?

Disassemble the alternator, replace the regulator and reassemble. With 76,000 miles, alternator replacement might be worth considering.

I checked out the codes for the Service Engine light and it turns out I have a defective coolant thermostat. So...that rules out any possibilities with a connection between that and the other problems.

In order to test if these problems are coming from the alternator, would I have to take the entire alternator in to get tested or is there another way to go about it?

Voltage output and maximum amperage output both need to be tested. You can test voltage by starting the engine and connect a volt meter to the battery terminals. When the battery is fully charged, engine at 2000 RPM, voltage should be steady around 14.2 volts. If the voltage varies, it will cause the lights to flicker. The maximum amperage output test requires an ammeter capable of measuring up to 120 amps and then applying battery voltage to the field, might be easier to take it in and have it tested for that.