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| Need help!! Persistent chugging/misfire issue (Page 1/1) |
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842m4SE
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SEP 07, 07:10 PM
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My 1984 Fiero with the stock Duke has had an issue since about January, where at more than ~20% throttle it'll "chug"/misfire rapidly, and lose a lot of power, but would start smoothing out around 3000 rpm and have few chugs above 4000.
Since then, I have replaced the coil, which didn't change anything, and then replaced the distributor with a new Delco reman unit that fixed the problem for about 50 miles before it came back again, but not as bad as before. Now it is completely fine for about 3 minutes after starting it up, and then it gets the issue, but not as badly as before. Rather than rapid-fire chugging, it will have some chugs under throttle going up the rev range and smooth out around the same point.
This persistent issue makes me hesitant to drive the car as I don't know if this is damaging ignition components, and it makes it much slower than it already is... I want my Fiero running smoothly again.
Relevant parts replaced so far: Battery, distributor, plugs + plug wires (last year), ign coil, ICM (with dizzy), fuel pump + fuel filter (last year).
Any advice or suggestions would be greatly appreciated, thank you.
Short clip demonstrating how bad the issue was before the distributor swap - https://www.youtube.com/shorts/Y46igxXp3Bk[This message has been edited by 842m4SE (edited 09-07-2022).]
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theogre
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SEP 07, 10:47 PM
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check the EGR valve.
While EGR is dumb system for 4cyl... ECM expect it working right and not leading vacuum or exhaust.
Some new ignition part is bad.
Wiring in engine bay have problems and often the ECM have problems seeing ignition etc. Check all grounds bolted/screwed to engine and frame there @ minimum.
+ Battery cable and others can short to ground when engine moves during accel, stopping or both.
See my Cave, Wire Service and other sections...------------------
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
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