Hello, I bought my 86 fiero GT 2.8 auto about a month ago and it is super fun. However I am having an engine issue I can’t find.
Symptoms:
-Upon a cold start it fires as I turn the key but will instantly die when I let go unless I press the gas pedal. I must hold the gas pedal for 20 or so second or it will die.
-If I let go of the throttle too quick or put it into gear without pressing the gas (again only while cold) it will die.
-It idles really rough but smooths while warm. If carb cleaner is sprayed into the throttle while idling cold it will instantly die.
-Instead of a 2 second prime with key on the fuel pump is always on, unplugging relay turns off, switching relays has no effect. (Separate issue?)
What I have tried to diag:
-Cts was shorted, replaced and fixed any issues for when it was running warm, cold was unaffected.
-FPR has been replaced.
-Unplugging MAP while running makes it surge/die so it is at least doing something
-Unplugging IAC makes it surge as well. Air passage for IAC has been sprayed with carb cleaner.
-New spark plugs (had weird bosch ones in it w 2 ground points, have been replaced with stock acdelcos.
-Went over vaccum hoses, replaced suspect ones. Capped the EGR ones (egr was deleted before my purchase but solenoid and vacuum lines left)
Anybody got any other ideas?
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Thanks!
Nathan Shade
"The Cheese Wedge" Yellow 86 GT 2.8 auto with a blue roof.
[This message has been edited by nathanninjacube (edited 12-10-2025).]
