:( HI, I HAVE A 1986 PONTIAC FIERO 2.5L. 5 SPEED, MANUEL TRANNY W/A/C. GAUGE SHOWS IT TO BE OVERHEATING..SO I REPLACED THERMOSTAT SINCE THIS DIDN'T HAPPEN ALL THE TIME. NO LEAKS NO HISSES THAT I CAN FIND ANYWHERE...EVERYTHING FULL ON FLUIDS. MY OIL PRESSURE GAUGE DOESN'T WORK AND NEITHER DOES MY FUEL GAUGE. IS IT POSSIBLE THIS GAUGE DOESN'T WORK EITHER? WHAT ELSE COULD BE MAKING MY CAR DO THIS? GAUGE SHOWS OVERHEATING AFTER IT'S RUNNING FOR AWHILE OR IDELING. YES, THE ELCTRIC FAN WORKS AND STAYS ON...IS THERE A FUSE FOR THIS GAUGE AND IF SO WHERE? IS THERE A SENSOR OR SOMETHING THAT WILL CAUSE THIS? CAN'T FIND ANY REASON FOR THIS...THANKS CHERYL
APPRECIATE YOUR HELP

Welcome to our site . . . I personally don't have any information on your issue, except to say that it does definately sound like an electrical problem with one single cause for all of your guage issues.

The temp guage is definately not reading correctly, as is true for the others.

Try these:

http://apollo.pacificweb.net/~sketch/osg/osg.html
http://www.hands-on.org/pfkb/
http://www.fierotech.com/

I found these few sites while scouring the web for information to help you. Unfortunately I found nothing, and I can not vouch for the sites that I posted . . . I just hope that you'll find what you're after . . .

I HAD THE SAME PROBLEM WITH TEMPERATURE GAUGE ('84 FIERO)
IT IS THE GAUGE.SUGGEST AFTER MARKET GAUGE OR WAIT FOR IDIOT LIGHT (BUT THAT MAY BE TOO LATE)

Its fooling you. Our oil pressure gauge don't work either...one bump it reads 60 the the next is shows none at all. What happens here is the needle in the guage gets what i call "Vibration or bump fatigue". I know this happens to alot of Fieros. Now as far as your problem with the over heating....You should probably replace the gauges. I know that the gauges in those cars were not made of miles and were never always right.

www.fierostore.com is a great place to get parts for your car. :) The parts they offer are made to fit fieros and have great people and great prices.

If you have any problems let me know.

Fieros had issues with overheating.

When the 4cyl ran low on oil it wouldnt notify you, and bam, piston goes out the side, oil pours and and yep, ingridents for a fire:)

Id be very careful. If it says its overheating, try and fix it. Dont be fooled by guages.

ingridents for a fire
Yes they been known to catch fire. Thats a fact.

Fiero's did have a bad reputation for a bit becasue they had some defective rods and gaskets, as any new cars things can go wrong and unfortinitally oil dripping onto a manifold does create fire....rods were crappy but these little 4cyl engines (note ont the 2.5L 4 bannger was known for this) it had a redline of 5000rpm, an orange line of 4500rpm, if your smart you wont take these engine past 4000... they just wernt built strong and alot of people seem to think these engines out of grama/grampa cars can handle 6000+rpm out of a pushrod engine...