rapping noise after spark plug change

Lol, done scared the stuff outa me too! But was short lived. Didn't last long. The only reason I disconnected the 12V was to get, check to see if the check engine would turn off. Which it did.

Was hoping that would be of more help.

Don't understand why your not getting any warning lights if it's misfiring, shaking? Would think Hal would be overly precautionary.

Hate the needing a computer to talk to the computer thing.

 

+1

I had a misfire on one cylinder on my Gen-2, and it made a horrible racket -- sounded like the worst rod knock I'd ever heard. It triggered trouble code for misfire on Cyl-1. Cleared the code, swapped coils 1 & 2. Started it up, same sound but with a code for a misfire in Cyl-2. Solved! New coil fixed it.
Do you have access to another Toyota you could borrow a coil from for diagnostic purposes?

 

Some things will give you an immediate check engine light and some are delayed. I believe misfires have to add up to a certain point before it triggers the check engine light. I know a MAF sensor disconnected will give you an immediate Check Engine Light.

Here is the information.

Blind Logic
Any misfires that are detected are recorded and tracked over time. If the rate of misfires exceeds a certain threshold, the OBD II logic is programmed to log it as a potential emissions failure and set a misfire fault code. The check engine light comes on and a P030X is set where X corresponds to the cylinder that is misfiring.

Misfires in OBD II Engines: How to Detect

 

So are all the problems gone now, is it fixed?

 

Yeah, I bought a set of "OEM Toyota" spark plugs for my 2013 -- can't remember if it was from Amazon or eBay. They came packaged in boxes labeled "Genuine Toyota/Lexus Part", "Made in Japan".

The package was shipped from China.

So if I'm to believe the seller, these "OEM" parts were manufactured to Toyota's stringent quality standards in Japan, then exported to China, before being sold to me... hmmm, seems unlikely! The boxes were not of comparable quality to those used by Toyota: thin cardboard, glued seams not staying together.

Lesson learned.

 

Wow Ken! Scary stuff. Glad they didn't do any real damage!

An' thanks for posting how it ended up

 

You can read all of this if you’d like, but long story short...the fix is to remove the spark plugs and check that the gaps were not changed during installation.

I had the same issue with knocking after a spark plug replacement. The first issue was misfire detected in cylinder one. After resetting the engine code and some drive time, the check engine light came back on but this time showing misfires in cylinders 1 & 2. I pulled all four plugs, only disconnecting the wiring on cylinder 4. Cylinder 2 plug was loose in place and some oil was present. Keep in mind these are original plugs with 172,000 plus miles on the car. I put in Motorcraft replacement plugs. Once I started the engine, the knock began.

I read some of these posts and tried the 12V disconnect, but the knock continued anyway. My code reader isolated the problem to misfire in cylinder 4. I pulled the new plug from cylinder 4 and found the gap closed at some point during installation. I pulled the remaining plugs to check for similar issues. None of the other plugs had the same issue. I re-gapped the plug and reinstalled it in cylinder 4. This fixed the knock instantly.