Misfire on cyl1 & cyl5

This morning while on my way to work, my car literally started flashing its CEL at me. As soon as I hit the gas to make the right turn from getting off the freeway off-ramp, I knew exactly why. Engine misfire. As soon as I got to the office a mile or so from my exit, I busted out my OBDII scanner to see what was going on, and I've got a misfire on CYL1 and CYL5.

The worst part is that I don't have my tools with me since I've been working on my other car and they're spread out all over underneath its hood right now.

I'll go home today taking it real slow and easy and check it out as soon as I get home. I'm just worried if having the misfire will cause any other issues. My one big question is, why do I have a misfire on two cylinders at the exact same time?!

Early 6th gens had a distributor on the V6 and later ones had coil packs. I'm not sure what your car has. Can you report? Also, any other codes besides P0300, P0301, and P0305? There is a green connector on the alternator that is known to have a diode in the circuit that is apt to failure which will cause misfires on the I4 with the distributor system and usually throw a P1381 code I believe. You can simply test for that failure by unplugging that connector and seeing if the misfires stop though I'm not sure if it would affect a ignition coil system. Did you feel the misfires?

Ever done maintenance on your EGR system?

Obviously, when you are back to tools, pull the plugs and see what you find.

^I believe they switched to coil packs in 2000.

You've had misfire problems before, haven't you?

RedRyder said:

^I believe they switched to coil packs in 2000

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I think you're right. Everything was a weird crossover from the 6ga to the 6.5ga and I think this was one of the changes in 2000.

james'99 said:

Early 6th gens had a distributor on the V6 and later ones had coil packs. I'm not sure what your car has. Can you report? Also, any other codes besides P0300, P0301, and P0305? There is a green connector on the alternator that is known to have a diode in the circuit that is apt to failure which will cause misfires on the I4 with the distributor system and usually throw a P1381 code I believe. You can simply test for that failure by unplugging that connector and seeing if the misfires stop though I'm not sure if it would affect a ignition coil system. Did you feel the misfires?

Ever done maintenance on your EGR system?

Obviously, when you are back to tools, pull the plugs and see what you find.

Click to expand...

I have a 2000 with coil packs. The codes are just the ones you listed, P0300, P0301, and P0305. Yes, I did / can feel the misfire as well as hear it. The only thing I was able to do when I parked it at work was check the coil pack wire harness to each of the cylinders. They were snugly connected, but I disconnected them and reconnected them anyways just to test, but nothing changed.

I have done maintenance. Last summer - June I think it was - I replaced my valve cover gaskets along with a few other things. On my way there, I cleaned out the EGR port. When I did clean it, it was still relatively clean from when I had done it previously about 2yrs before.

RedRyder said:

You've had misfire problems before, haven't you?

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Yes I have.

When you had misfire issues before, what ended up being the result? Just wondering.

The most common reason for my previous misfires have been the "heat soak" issue. There's a thread about it here somewhere. The other reason for my misfire was that one time that cyl 2 blew up.

2000 = individual coils

Suck-squish-bang-blow

you've got some suck, we'll take it as credit for now though
squish, we can assume your compression is ok, check it later
BANG, no bang, one second, I'll explore that
and blow, again, assuming you have for now

so bang requires AIR, you got it, FUEL which we need to check, and a SPARK, the easiest to check, cause you have coil packs.

1 & 6 get swapped with 2 & 5 coils, see if the code moves.

REMEMBER
wiring for cylinder 1, stays with cylinder 1, not the coil! The coil may freely move around.

If that makes sense, there are too many ways to use all the words I can come up with to make that bit clear.

Swapping coil packs, checking plugs for fouling, and checking spark were the things that I am going to check for sure once I get a hold of my tools.

I'm curious as to why this happened on two cylinders at the same time.

xci.ed6 said:

so bang requires air, you got it, fuel which we need to check, and a spark, the easiest to check, cause you have coil packs.

1 & 6 get swapped with 2 & 5 coils, see if the code moves.

Remember
wiring for cylinder 1, stays with cylinder 1, not the coil! The coil may freely move around.

If that makes sense, there are too many ways to use all the words i can come up with to make that bit clear.

Click to expand...

+1