My car was fine when I turned it off. Now it is running rough. Everything was pointing to a bad ignition module on the distributor but it doesn't appear that my car has one. The plugs wires are arranged in a line under the intake manifold like it has coil packs. Does anyone have experience with this?

So you have an 87 or 88 4 cylinder.....

There is a crank sensor mounted to the plate (that's the ignition control module) that the coil packs are mounted on.
They are known to fail, as are the control modules.

The car is an 87 but it has had an engine swap. If might be an 88 motor. I helped my dad put it in back in the 90s when it was his but I don't remember what it came out of.

I believe the #2 cylinder isn't firing. It was the only wet plug and it didn't run any different when I took the wire off of the plug.

The coil pack on the later Duke engines consists of two coils each firing two cylinders. The ignition control module fires each coil twice in every rotation. If all cylinders are firing except #2 then I suspect a defective ignition wire or bad spark plug. It could be the module but the same coil that fires #2 cylinder is the one that the module fires on #4.
I would start wtth new ignition wires and spark plugs,

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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 "

You may find this article from the Forum to be beneficial.....

Servicing GM Direct Ignition System https://share.google/fwCoNSjcDS2PxmmzK

quote Originally posted by olejoedad: You may find this article from the Forum to be beneficial..... Servicing GM Direct Ignition System https://share.google/fwCoNSjcDS2PxmmzK

That is a good article with one exception. You do need thermal grease under the ignition module or the coils. Ground contact is established through the baseplate and grease can disturb that. The GM manual just says to screw everything together and tighten, no mention of any grease needed but perhaps Fiero Dukes are different. You definately need thermal grease under the V6 ignition module,

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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 "

[This message has been edited by Dennis LaGrua (edited 06-30-2025).]

It's MISSING?!

We will do whatever we need to do to help you find it!


(sorry... I know, I apologize, I couldn't help myself)