1988 GT 2.8 V6
It hasn't always done this, it just recently started.
Gauge needle seems to operate in wrong direction.
Disconnect temp gauge connector, ground green warning light wire, warning light comes on.
Grounding green/white gauge wire, gauge pegs left.
As car warms up, gauge moves left until it pegs up in the foam.
Turn switch off and needle drops to about the 8 o'clock position.
Key in 'Start' position does not bump needle to full right peg as it used to do.
No wiring mods have been made.
I'm thinking gauge is the issue.
Any ideas from you guys?

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1988 Fiero GT, 5 speed

Oil and Fuel pegs full right when related senders disconnected
Can remember which side the Temp does same.

Gauges have resistors on back and "nuts" for them get loose or dirty. Only see them when gauges are out of dash.
Then have clips between gauge and "board" on back of dash. Dash Plastic warps etc and copper get dirty then clips don't connect well there.
If anyone pulled the big connector on back of dash the copper can get loose and easy bend trying to replug those.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

I may not be correct in the assumption that the Temp Gauge Needle is pegging? There is a electrical design flaw with the 1988 Models (as well as other years), where the temp needle will pegged to the right when you turn the ignition switch. There are many articles on how to repair this problem. The Previous Owner that I bought my car from, tells me “No Problem” just to hit the top of the dash hard with my hand, what made me nervous, is that he was a former Commercial Airline Pilot.

When testing the gauge by grounding the sending unit connection, the proper gauge response is to peg to the right.
When testing my system, the gauge pegs left.
It also arcs left as the temp rises.

The coolant temp gauge schematic shows only two wires to gauge.
One is the green w/ stripe (sender resistance) and the other is ground.
The same ground point (G201) is used for the temp gauge, fuel level, and tachometer.
The others operate properly so at this point, I'm assuming the ground is solid.
There has been no wiring touched or modified in the gauge harness area.

quote Originally posted by Eliredandblack: former Commercial Airline Pilot.

Amazing he's survived to tell you that. I was on vacation years ago at Niagara Falls and we went up in a helicopter for a better view. The oil gauge was on "0" and I tapped on it figuring it was stuck! It wasn't and I had wife and young boy along as well. The pilot just gave me a big smile as if nothing to worry about.
Our only possible salvation was we were flying over water and there hadn't been any known helicopter crashes recently. It was a bit unnerving.

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

[This message has been edited by Spoon (edited 12-04-2022).]