1999 Buick LeSabre problem

Good morning guys, having a problem with my 1999 Buick LeSabre with a 3.8 6 cylinder engine. I’m getting an engine code P 301 from my scan tool. Also reads 01/ 02 misfire I changed my plugs and wires thinking that would eliminate the check engine light. Still getting the same code except now the check engine light flashes rather than stays constant. After I cleared the codes it flashes all the time. I am assuming the 01 / 02 is saying there is a problem was cylinder 1 & 2 or cylinder 1 & 2 any ideas after changing plugs and wires the car still does have a little bit of a Miss to it. Any suggestions you have on what else to check would be helpful and as always thank you for your time

I think that engine still used a 3 coil pack that paired 1 and 2 on the same coil. The coil has very likely failed causing the misfire. I think you have to replace the entire coil pack.

Don’t drive the car with a flashing cel.

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Beat me too it.

Are you sure the plugs are the exact model and gap specified by the carmaker? If there are multiple coils, try exchanging the one for 1&2 with another one.

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It would appear two of the coil packs have failed.

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Tester

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If that’s the case, might as well replace all three as preventative maintenance. The third one can’t be too far behind the other two.

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I’d swap coil for cylinder 1 and 4 with coil for cylinder 3 and 6 and see if the misfire moved from cylinder 1 to cylinder 3, if possible. Looks like they just bolt on there.

Probably a good idea to check the wiring from that bank of coils. I think all the wiring goes through a single connector that could be loose or corroded. I kind of have my doubts that 2 out of 3 coils went bad at the same time.

The wiring plugs into the ignition control module which the coils plug into.

And I’ve seen more than one coil fail on these wasted spark ignition systems

Tester

So the coils sit on and plug directly into the icm? I was recalling putting valve cover gaskets on my 4.8 liter GM truck engine, had to remove coils from valve cover. Can remove the entire bank of coils by unplugging one connector. Thought this might be a similar setup.

As far as the two coils failing at once, I’m still a little skeptical. In all my GM driving, I’ve never had a single coil fail. Plenty of other stuff has failed, but never a coil. So two at the same time failing would definitely be possible, but I’d be a little surprised.

One important fact I forgot to tell you guys my bad, I put a spark tester on the plug and it is getting spark, that’s why I didn’t change the coils because spark was getting to the plugs

No, ACDelco came out I put in n g k positive there Gap properly but I did cross reference according to Advance Auto Parts the NGK should work I’ve always used NGK plugs but could that be a problem?

I forgot to tell you, and I apologize for not telling you. But I put a spark tester on all the plugs and the spark tester was firing nicely, that is why I ruled help the coil packs but could I be mistaken?

Scrap yard John, with a spark tester showing me that I’m getting spark to the tip of the plug would that rule out the coil packs? I thought it would. What you guys would know better than me and once again thank all of you guys for your answers and help

Your replies are seen by everyone so no need to repeat your replies to each person.

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Try swapping injectors to see if the miss moves with the injectors.

Tester

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NGK are pretty good plugs, usually. I do prefer to put the exact same plugs that came out from the factory back in there, though because some auto makes seem to be kind of finicky about plugs.

But, I’m assuming you had the problem before you replaced the plugs and the problem didn’t change much one way or the other after the plug change. If that’s the case, I’d assume the new plugs aren’t the problem for now.

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New plugs and wires did not help at all thanks for the info

Time to do a compression test to determine if the rings and valves are in good shape.

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Going to pull the fuel injectors, and clean them. And if that doesn’t work then I will try the compression test. Right now I got to wait till this heat waves over, it’s just too dadgum hot to be working on that car. But as always thank you for your time

Are you guys ready for a good laugh, after changing the plugs and the wires in my LeSabre, I forgot to erase the old codes. And of course when I checked it again the old code was still in there. After erasing the codes and running the car for an hour no check engine light it’s running perfectly. I think I can hear people laughing, out my window, as always thank you guys for all your help I appreciate it

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