I have a 97 SSEi with 164000 miles on it. I've been having crazy electrical issues with it. I have a zzp pcm in it. I have an optima red top and a one year old alternator. 0 gauge wires for the big three when I had my subs running at 2200 watts. The subs are out of the car. Right now I have a Pioneer dvd head unit that I had professionally installed this time. On to the problem, my voltage fluctuates like crazy. When I start the car sometimes it will run for a few seconds and then die. I can start it right back up and it'll die again. My battery and alternator have tested out okay three times in the last 3 months. I've tried to get the car to stay running by wiggling all of my connections but nothing helps. Again this problem is intermittent. As in maybe once a week. But the voltage fluctuation is constant. It used to drop under 12 volts while at a stop in drive with the brakes applied. Still does occasionally. I also have a viper security and remote start that was installed by American. I cause a spark when attaching my cable to the alternator because the cable to the battery accidentally touched the post. But again the alternator and battery both read ok. Any ideas or suggestions are greatly appreciated.

First, look in to this, https://www.gmforum.com/electrical-133/adding-sense-wire-your-alternator-278806/

Next, check over your battery cable connections. Side terminal batteries have a problem with corrosion. This can cause a stall, or no crank.

I checked all of the wires. Retested the battery and alternator. My biggest problem is that the car will start up right away and then die. Repeatedly. It seems to want to do it when it wants. She'* going to end up in the scrap yard here shortly. I've changed the fuel pump, fuel filter, spark plugs, and wires all less than a year ago even though they were all still in perfect condition. Well, outside of the pump taking a dump on me. I'm at the end of my wits with this car. It'* a very good car, but so many problems now. Any help is greatly appreciated. I can't find the issue and I'm fairly adept when it comes to cars, so again anyone who can help, my car would be forever indebted to you...

Locate your fuel pressure regulator, it'* on the fuel rail and has a vacuum line on it. Pull that off and smell teh vacuum line. If you smell gas, the FPR is bad. That can cause hot starting problems. Another area is the crank sensor. If it'* going bad it will stop sending the signal to send a spark.

Alright, I located the issue and you're probably going to laugh. The stud on the alternator that the battery cable is hooked up to was loose and just kept spinning. Just have to take it to autzone and have it replaced. Thanks for the suggestions. I have another question though. I'm losing coolant and I can't find any obvious leaks. My car isn't overheating and I'm not seeing any leaking around the the lower intake manifold either. I will get heat but only in park and sometimes it isn't real warm either. I have a 180 degree thermostat in there and I had the radiator flushed about 3500 miles ago. I lose the heat and my temp gauge drops down to nearly 100 while I'm driving. I'm assuming it'* caused by a leak since the coolant system is a sealed system. But I'm not finding coolant in the oil and the car'* idling fine. If you have any suggestions I would greatly appreciate it. On a side note and I know this is an odd request. My Bonneville is the same color as your pictures show but I was wondering if you did your hood like that or if you had it done and if you did do it would you possibly consider doing my hood and I'll pay you whatever you ask..

it sounds like your thermostat is stuck open, unless you have a tune you should get a good 195 thermostat to make the car run properly.

I have the ZZP pcm in there. As far as I remember it worked at 180 degrees. Although I just read on their site that it runs at 185.. If that'* the case do you think that may be my issue?

Over cooling only comes from a stuck open thermostat.

I made the hood myself. The problem with making it is shipping will kill you.