Camry misfiring on highway

[Trav]

You have a code so that would be a starting point. I got this a while ago and it has proven useful many times. Made in Canada not Chinese junk.

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[KS-Ryan]

I second this. It happened to me once about 20 years ago.

He should get a P0420 code if that is the case.

 

[53' Stude]

He should get a P0420 code if that is the case.

I had a P-0420 code last year, for cat converter. Replaced that with Toyota OEM cat converter in last July

 

[JMJNet]

Unfortunately, all parts can go bad no matter how old they are or where you bought it from including stealership.
Saying that part is OEM with so many miles do not mean a thing when there is something wrong with the car.
Everything has to be reviewed again no matter how old or new or OEM or aftermarket, etc.

OP just have to do a proper diagnosis.

 

[53' Stude]

Unfortunately, all parts can go bad no matter how old they are or where you bought it from including stealership.
Saying that part is OEM with so many miles do not mean a thing when there is something wrong with the car.
Everything has to be reviewed again no matter how old or new or OEM or aftermarket, etc.

OP just have to do a proper diagnosis.

No kidding.

I have to get car home then I can see what’s going on. Go from there

 

[javacontour]

200k is about the time I replaced one of the coils on our 2002.

Still, get the code and do the test I suggested.

Also look for oil in the plug well. If the VC gasket is leaking there, the plug well may fill with oil helping cause a misfire.

 

[53' Stude]

200k is about the time I replaced one of the coils on our 2002.

Still, get the code and do the test I suggested.

Also look for oil in the plug well. If the VC gasket is leaking there, the plug well may fill with oil helping cause a misfire.

Well JavaContour here is the ugly. P-0301 and P-0303 codes. Just what I didn’t need. And it’s pouring rain here. I did replace the valve cover gasket with Toyota OEM One when I did spark plugs. Rechecked tightness 2 days later and still good. I’ll update this someday, or when I figure it out

 

[javacontour]

Well JavaContour here is the ugly. P-0301 and P-0303 codes. Just what I didn’t need. And it’s pouring rain here. I did replace the valve cover gasket with Toyota OEM One when I did spark plugs. Rechecked tightness 2 days later and still good. I’ll update this someday, or when I figure it out

Thanks,
I think I'd still try something similar like just swap the 1-2 coils and the 3-4 coils and see if the problem moves before loading up the parts cannon.
My money is on coils if I were guessing with my wallet. But I'd probably want to replace the plugs first as they are less costly.
Either way, hope you get it sorted soon and yes, keep us informed.

 

[53' Stude]

Thanks to javacontour and everyone for help. Both coil packs were bad. Cut out of work early and checked everything over. Plugs didn’t look bad at all. Cleaned all them off and dried them and checked gap and reinstalled.

 

[JeffKeryk]

Thanks to javacontour and everyone for help. Both coil packs were bad. Cut out of work early and checked everything over. Plugs didn’t look bad at all. Cleaned all them off and dried them and checked gap and reinstalled.

Where did you get the new coils? Napa? How much? Don't cheap out or you will be reght back there again.
Don't ask me how i know...

 

[53' Stude]

Toyota OEM from our Toyota dealer. Lil over $130~ my price so not terrible

 

[javacontour]

Toyota OEM from our Toyota dealer. Lil over $130~ my price so not terrible

Glad it got sorted.

I had to replace only 1 in 277k miles in or 2002, so hopefully two is all you need to replace while you own this car.

 

[01rangerxl]

Do an exhaust back pressure test after checking the coils. This is also a symptom of a clogged cat.

Yes, obviously a totally different vehicle, but this is exactly how my Ranger was acting when the y pipe converters were failing.

 

[zzyzzx]

I have been burned 3 or 4 times on fake NGK plugs from Amazon. Pull one or two and look at the electrode. The fakes I got had worn, rounded tips in less than 40K.

It happens and is maddening. Good luck.

Then don't buy NGK plugs.

 

[JeffKeryk]

Then don't buy NGK plugs.

NGK makes great plugs. That's not the problem. The problem is Amazon selling fake NGK plugs.

 

[Lubener]

Might not be ignition related. I would believe if the misfire occurs long enough, the CEL should come on with a code set.A vacuum gauge can tell if the cat is clogged as was suggested. ..

Get up to speed where the symptom appears. Hold your foot on the gas to maintain the speed and then press on the brake lightly to see if the symptom goes away to see if its transmission related...

 

[zzyzzx]

NGK makes great plugs. That's not the problem. The problem is Amazon selling fake NGK plugs.

Denso makes great plugs too. So do a few other less likely to be counterfeited brands.

 

[53' Stude]

Might not be ignition related. I would believe if the misfire occurs long enough, the CEL should come on with a code set.A vacuum gauge can tell if the cat is clogged as was suggested. ..

Get up to speed where the symptom appears. Hold your foot on the gas to maintain the speed and then press on the brake lightly to see if the symptom goes away to see if its transmission related...

I highly doubt it’s a clogged cat converter. Especially since I put a new OEM one on last July. Obviously I did have a check engine code before I diagnosed the problem as I verified it with my scan tool.

 

[FZ1]

I highly doubt it’s a clogged cat converter. Especially since I put a new OEM one on last July. Obviously I did have a check engine code before I diagnosed the problem as I verified it with my scan tool.

Go back and recheck the last work you performed on the car. .02

 

[JeffKeryk]

Denso makes great plugs too. So do a few other less likely to be counterfeited brands.

Agreed. Our TSX, with the mighty K24, had 2 NGK and 2 Denso plugs from the factory.
I won't buy any plugs from Amazon anymore.