Gauge Issue, reinstalled dash after removal

Thanks a lot for your reply.. After fooling around with it for a few more hours, the only unconnected thing I can find is the actuator solenoid that locs the shifter in gear.. lol.. nice, but still no help. It's a 95 Mustang. I also have another cluster from a salvage mustang and tried that temp/fuel pressure gauge assembly, still nothing. The funny thing is, the voltometer was acting up with the heater before I began to redo interior, but the temp/speedometer wouldn't work at all. lol, ee since I reinstalled everything, the speedometer works fine, and so does the temp guage, gas is just dead. The car runs a little groggy too, especially in like 4th on the freeway shaking and such, with pulsating brakes at high speed... I cleaned the AIC, replaced air filter, used MAF cleaner on the MAF...

The Car used to wait a few moments to shut off, but after I either loosened the screw on the throttle body to lower idle (which to my understanding isn't even the proper way to adjust the idle on a 3.8, all done by PCM?) it shuts off fine now.. I did the idle reset where you wait two minutes with accessories on and off after unplugging the IAC Harness.. runs a little better but still I am at a loss, lol. If it makes a difference, the engine cooling fane was hotwired to run anytime the ignition was on, which I disconnected because it is winter here in OH and the fan isn't really necessary (or so newbly assume) to keep the engine cool as the temperature guage appears to be working... also, after driving like over 50 MPH, the oil pressure gauge will fluctuate UNTIL a little acceleration is given OR if the gear is placed in N, and the clock will also randomly shut off....

Are there any pigtail connectors I may have missed during install in the actual interior? I had everything stripped including carpet to the bare metal.. Once again any input is greatly appreciated I have been working so hard on this car I have had it since I was 16 bought it for $500 and it has come so far from the day I bought it... Since last September I have probably put over 250 Hrs of my free time into this thing, a vast majority trying to understand and try things that dont wind up even working...

Sum up off problems:
Fuel pressure Gauge never moves off of "E"- It may be important to add I did remove the needle at one point, but I secured it as much as possible.

Voltometer fluctuates with AC/Heater Operatio (Oil Pressure will also fluctuate very minimally)

Oil Pressure Gauge ERRATIC after a highway drive during Idle, such as at a stop light, returning to steady nurmal with a slight acceleration or gear switch to Neutral.

Dash Clock will randomly turn on and off, never storing correct time.

Pulsating breaks (Only at High Speeds)

Vibrations at higher speeds when in what appears to be 4th gear...

lol I know its a lot but any input on any matter would really be such a blessing..
Thanks!

Just because the inside was garbage.... tan stock interior on black with scratches and blown airbags... I got two new airbags, but didn't plug them in b.c I didnt want them to pop ha I dont know how that works.. The weird thing is that the I tested for power from the wire thats is supposed to be hot for the fuel and its ground... I used a dremmel and removed the ashtray light and the ashtray accessory outlet, Elec taped them off and put in a cup holder from an 04.. I really wish that someone could just list all the interior grounds... I have searched high and low and nothing.. lol wow I gotta say it feels so weird actually taling to someone on here I felt like it would be such a waste of time b.c nobody would respond... Another issues I hav, which isnt the biggest for me, is I managed to get all the power doors working, which took forever... the only button that doesnt work is the lock/unlock button on passenger door. it is like a continuative electric path I can hear like a moving noise, as if the reverse polarity doesn't work... hmm... I really am wondering if it has something to do with a plug I missed, but before I removed anything, the voltometer would fluctuate with heater, and oil would mess up a little too, so idk... another thing

I removed my cd player, and I found a whole bunch of plug ins? Mycd player worked fine, but the wires were weak ghetto best buy stuff... then I found a big heaping pile of wires taped up behind the console, untaped it, and it was aother two pigtails hacked up for another after market cd player that must have been in the car, cleaned that one up, and used it instead of the one I was using, only thing is it appears I missed plugging in my cd players 12v amp cuz it isnt as powerful, but as far as waulity it is better b.c I used both of Fords factory radio grounds so now my cd players illumination doesn't flash with bass... I am assuming that the extra wires is because there was probably a seperate harness for radio and cd player from factory, but idk.. I am gonna go play w it for a while until it gets dark... could it have anything to do with the wires in the light switch? I noticed upon removal during my project that one f the metal peices appeared shot? but no problems with the lights... I also have a after market gauge illumination face from American Muscle... A kill switch my dad installed on the yellow and red wires which prevents the ignition from connecting to the starter if unengaged... Hmm, I guess I will play with it a lil more... ha, I have done a lot I will have to put some picturs up.. I am mostly proud b.c I am really new to this, and a lot of what I have done I have done w.o spending a lot of money, like I used a dremmel and flushed the original pony grill emblem into the arm rest, and put an 04 Grill on my 95 with newer headlights from american muscle... well, It'll be awesome if we figure this out I will never get rid of this thing!

Breakthrough

Haven't fixed all the problems, but fixed the Fuel gauge, I think... I lossened the needle, it was on pretty tight and couldn't move... It wasn't accurate so I went down the street, filled her up all the way, removed the gauge used a auto body tool to remove those push in upholstery screw things to move it without moving the the small metal pin, and gently put it on full.. it seems to work, but then again, I guess I wont know until I use up some of the tank.. it was slightly fluctuating between completely full and the other side of the Full "-" dash line.. but when I put the car in to run, before starting, it starts to drop until fuel pump kicks in then moves up to full so I think I may have fixed it.. One problem down!