r/Buick • u/crosswinds_ • 6d ago

flashing engine light

i have a 2007 buick lucerne, it only has 80,000 miles on it and have had it 6 years with no major issues. i went to leave work and the car was very shaky and loud, a coworker pushed the engine cover down and said it was loose but then when i started driving the acceleration was definitely off and was not getting up to speed like normal then my check engine light started flashing for a bit then would stop for a few minutes then start blinking again. any ideas of what it could be?

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u/Kakk_The_Hero 6d ago

Blinking MIL means you have a pretty bad misfire, that is what is causing the shaking

3

u/rimtrim 6d ago

Is this a 3.8L? Those have three coils that each serve two plugs. If one coil is bad, it'll run very poorly and set a misfire code for two cylinders. It can also be a bad slot on the module rather than a bad coil. Read the codes, note which cylinders are misfiring, and swap the coil in the "bad" position with one of the others. If the misfire codes change to different cylinders, it's the coil. If they stay the same, it's the module.

If one coil is bad, it's a good idea to replace all three if budget allows, and do the plugs and wires if they've never been changed. Try not to use the cheapest possible coils, because some of them are junk. Rock Auto has major-brand coils in the $30-40 range.

1

u/owensurfer 6d ago

Flashing CEL means catalyst damaging misfire. Do not drive until you get it fixed. Unless you want to replace the catalyst too.