This is going to be a long one, so grab a beer So here is the situation fellas: I am currently restoring a 92 RS with a TBI 305. I seem to have a poltergeist lurking deep inside of my electrical system that tries to make the car stall at low rpms. The car rpms drop down intermittently below 400rpms and it tries to stall but can be throttled back to life. This happens most often when electrical systems are turned on (window motors, turn signals, cooling fan). When a select number of power drawing systems in being utilized, a large voltage drop can be seen on the dash. The drop can be as severe as dropping from 14ish volts to 5ish volts. When this dip occurs, the car struggles to stay alive and the oil pressure drops when the engine stumbles. There are some other strange issues that may or may not be related. For instance, the center console area including the radio and swifter plate gets relatively hot to the touch and stays that way. Sometimes, but not always, when I turn the car on, the rear right speaker's bass will flap extremely quickly and extremely loudly regardless of radio volume. The flapping speed increases or decreases depending engine output. After awhile the flapping will subside and the speaker will function just fine. One day in the recent past, I lost bass on all of the other speakers, and it has yet to come back. The trunk motor stopped working for a month, but now works just fine.

I've tested the alt and it was fine, the battery is on the weak side, but still in the acceptable range, and after a brief visible inspection, now wires seemed to be broken. Another thing to not is that once the car has run for awhile, the engine doesn't try to stall out and the speaker issue subsides. However, after I drive for a little while (15-30 minutes), I get a check engine light that goes away every time that I restart the car. Also, at high RPMS and under a load (like on the highway) rpm drop does not occur.

I'm at a loss on how to fix this one. Any suggestions would be greatly appreciated!!!

Well without physically looking at your car, first thing i would do if you insist on driving it is, i would invest in a couple of fire extinguishers. Then i would pull the codes from the CEL ALDL, and then i would completely go through all the wiring before you burn it up. https://www.thirdgen.org/service-eng...ht-error-codes

I kind of have to drive it, the car is my daily driver. Also, these problems have exhisted for over a year without getting worse. They just kind of are there and I deal with them. Also, I have a code reader, can I plug that directly into the computer?

I replaced the battery, and although it did not fix the problem, it did make me aware of the wiring nightmare to come. There was an aftermarket alarm system installed under the dash board. the whole area under the dash is one big mess. It is a rat-nest of broken wires and relays thrown all over the place. Does anyone have a wiring diagram or pictures of what the area under the dash should look like? I want to fix it and return it to a stock setup without breaking anything.

I went through the same thing with my 91Z. There was literally about 15-20 lbs. of sloppy aftermarket wiring for stereos, remote starter, alarms under my dash, hood and carpet. It was a painstaking process of piecing it all back together. Lots of solder burns on my hands from that job. If I had to do it again I'd just find a used body harness. I think Hawks sells them...maybe some other vendors too.

I have the majority of a stock wiring harness to use as spare wires. I was thinking about using plug connectors or soldered connections to splice in the stock wires. I just need to know where everything goes. I only want to do this once, and I want to do it right

Sounds to me like you need to hook a ground strap or cable between your engine block and the firewall.

As far as the harness, take the dash out, with the harness attached. (the fuse box will come with it) Lay it on the ground and spread it out a bit. Won't be hard to see what's been butchered.

Where would be the best place to attach both ends of the ground cable?
Not a bad approach to solving the issue. Beats cramming up under the dash board. I fear that the issue might not be trying to identify what has been butchered, but rather to identify what hasn't been.