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Puzzling misfire and flashing check engine light

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Old 05-03-2018, 12:14 AM
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Default Puzzling misfire and flashing check engine light

I have a 2000 Protégé LX 1.6L. I installed new NGK Platinum plugs (see photos) a couple weeks ago gapped by the vendor, and all new coil on plug coils and plug wires and boots.

No spark leaks detectable. The air filter is clean & white. I sprayed hoses with carb



cleaner checking for vacuum leaks. No change in engine sound. Engine idles almost normally but while idling there is an occasional faint “poof-poof” sound that seems to come from the air intake manifold that coincides with a slight slowing of rpms. After half-minute of driving at highway speed, the check engine light that is always on starts flashing. Codes are P0301 & P0302, but plugs 1 & 2 look good and plug 3 is carbon-fouled. Upon advice from this forum, I've added a gallon of acetone to a half-tank of gas to clean the injectors, which I haven't checked. Does anyone have an idea of what I should do next? I'm stumped. Thanks for any help!
 
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Old 05-05-2018, 09:30 AM
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Swap the coil packs, reset the codes.
 
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Old 05-06-2018, 10:52 PM
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Thanks, Saudade. I actually swapped the old coils before I put the new ones on, but I didn't reset the codes. I thought that if a coil was bad new codes would follow the bad coil. The codes didn't change. But I see from your post that I should have reset the codes and watched for new ones to appear. I'll do what you suggest. Thanks!
 
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Old 05-08-2018, 03:40 AM
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Saudade, I switched the coils, reset the codes by disconnecting the battery, and drove until a code appeared again. Same code, Cylinder 1 misfire, but not Cylinder 2 misfire. Maybe yet to set Cylinder 2 misfire? Now what?
 
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Old 05-17-2018, 10:00 AM
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OK, just to be picky, why didn't you use the reader to reset the codes? What code reader are you using? Did you see any "Pending" codes?

Did you see the misfire before you installed the new plugs?

Carefully inspect the sparkplug wires and all of the boots for any cuts, tears or signs of arcing.

Use some dialectric grease to slick up where the boots slip over the plugs and the high tension leads slip onto the coil.

Clean the plugs, recheck the gap and swap them around too. Keep track of what plugs went where.

What the part number on the plugs?
 
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Old 05-17-2018, 11:25 PM
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Originally Posted by Saudade View Post
OK, just to be picky, why didn't you use the reader to reset the codes? What code reader are you using? Did you see any "Pending" codes?

Bobwilli: I was having to drive to a parts store to get a CEL readout. Now I have a reader myself. I reset the codes and switched plugs 1 & 3. Still misfire on #1.

Did you see the misfire before you installed the new plugs?

Bobwilli: Yes. That's why I got new plugs.

Carefully inspect the sparkplug wires and all of the boots for any cuts, tears or signs of arcing.

Bobwilli: OK. Will do. Thanks for helping me

Use some dialectric grease to slick up where the boots slip over the plugs and the high tension leads slip onto the coil.

Clean the plugs, recheck the gap and swap them around too. Keep track of what plugs went where.

Bobwilli: [later] I have switched the plugs, reset the codes, driven to set a new code: 1234, 2341, 3412. Each time code was P0301. I switched the sparkplug wire-and-boot between 1&3. Still P0301.

What the part number on the plugs?

Bobwilli: NGK ZFR5FGP.
I have also put in a new PCV valve.

I conclude the problem is not with the plugs, wires or coils.


Thanks, Saudade.
 
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Old 05-18-2018, 08:45 AM
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OK, Thanks. I agree. It's just easier to diagnose spark issues with misfires. So on to the fuel system.
 
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Old 05-18-2018, 02:53 PM
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Originally Posted by Saudade View Post
OK, Thanks. I agree. It's just easier to diagnose spark issues with misfires. So on to the fuel system.
Thanks, Saudade. Cylinder 1 injector? I’ve never messed with injectors. What do I look for?

[Later] The injectors are at least nearly 200,000 of 213,000 miles old, probably never replaced.
Time to replace them all? If so,
Rockauto: Which of these would you recommend, if any?: https://www.rockauto.com/en/catalog/...+injector,6224

[Update 2] Disconnecting and reconnecting electrical plug from injector #1gave little, if any, change in idle.

[Update 3] Compression test, psi, 1-2-3-4: 230, 220, 225, 220. Range: <5%

[Update 4] Switched injectors 1 & 2: Now injector order is 2134. Still P0301. When engine cools down, I'll switch 2 & 4. Order will then be 4132.

[Update 5]. Injector order as above, 4132. Still P0301.

[Update 6] Took out spark plug #1 and grounded the side of the plug. Cranking caused a spark to jump across the electrodes.

What can be causing a Cylinder #1 misfire code P0301 to be set?

CONCLUSION: I started to redo the electrical tests in case I made a mistake. One of the new COP coils I had installed to remedy the misfire was bad. When I switched them and reset the code, the code changed from P0301 to P0303. Switching the plug wires made no difference. Both of the old coils work fine now. I don’t get it, but I’ll take it. Probably my own mistake. Lesson learned: double and triple check my work.

Thank you, Saudade, for helping me with this. I learned a lot about my vehicle through it.
 

Last edited by bobwilli2; 05-30-2018 at 02:19 PM. Reason: More Updates
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