I have been repairing my fathers 84 stock Fiero over the past few months. We have been able to fix everything that needs fixing and replace everything that needs replacing but there is one thing I just cant fix: the gas pedal. It's very smooth and easy to push down when the engine is off and the cable that leads to the engine is completely where its supposed to be. Whenever the engine is running the gas pedal becomes hard to move at first and when enough pressure is given to break it free, it ends up going to high rev's since its basically at half throttle at that point. Once it breaks free from no throttle it is easy to push the rest of the range, but once you take your foot off, the initial push is hard again. As noted previously, it only happens when the engine is running, with the engine off it is easy and smooth to push initially (i.e. throttle 0-5%). I have been trying to adjust the screw on the side of the carburetor that adjusts the spring pressure on the butterfly valve (thinking it may be sticking with suction of the airflow down through it. After hours with messing with that screw the pedal doesn't get any easier to press when the engine is on. It makes it incredibly difficult to control low RPMs, i.e. when starting from a stop while driving it. I think its the vacuum / suction holding the butterfly valve down. If anyone has experienced this in the past, or any advice/thoughts, please let me know what i can do to fix it. I have looked online and haven't found anything about my problem. Thanks in advance!




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1984 SE

[This message has been edited by Terminator (edited 05-28-2022).]

Much of the time a sticking TB is caused by dirt, carbon, or gas varnish. Cleaners are made for throttle bodies or you can use carburetor cleaner but only on the butterfly valve.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Could be the TBI w/ problems like said above,..

Could be the cable(s), pedal assembly or all combine.

Examples:
Throttle Shaft will "eat" the hole in Carb/TB/TBI body over time and can cause binding. Often see metal wear in main bore where butterfly hits because of worn shaft hole.
Cables to pedal and/or AT can bind too.

Worse if fools use oil to "lube" them because most oils hate plastic and loves to hold dirt.

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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

Just wanted to comment that those two images that show up as icons are excellent photographs... but to avoid them appearing as clickable icons, try to keep the file size to a maximum of 2 MB apiece.