Replaced battery then idle got rough and check engine lights on!

I replaced my battery in my 98 Tacoma v6 sr5 yesterday then the idle became very rough. As well as the check engine light coming on and occasionally flashing.I thought it was just gonna be the ecm taking some time to relearn the idle but I became worried once driving it. While acceleration sometimes the truck would shake all gnarly. So i Took it to oreillys and got the diagnosis. Turns out cylinders 1, 3 and 4 are misfiring. The codes were (P0304, P0303, P0301 and P0300). No idea how changing my battery caused this but maybe it’s just an error???!? Help me out!!! Please and thank you!!

 

loose connection(s)?

 

Welcome to TacomaWorld

 

1-4 share a coil pack
1 is lead cyl pass side
4 is middle cyl drivers side
3 is middle cyl pass side

P0300 is random misfire on multiple cyls

Has it been humid (heavy dew,rain ) where you live ?
I’d check plug wire routing and coil connections first. Then maybe consider a good tuneup with quality wires including coil pack boots.
I’ve had plug boots blow out and arc inside the tube when humid or heavy dew. Coil boots as well.
Replacing the battery was probably just a coincidence event

 

I'd check the connections too. Clean the terminals really well and check the ground connections as well. If all you did was replace the battery that's most suspect.

 

I live in Hawaii so it’s very humid but not more than normal. I’ll look into the wire routing

 

A flashing CEL means
STOP
TURN OFF ENGINE

 

Don’t freak out!
You just need to clean the butterfly on the throttle body. After a new battery is installed the computer is reset. Most commonly on Toyota’s the butterfly position is very fine tuned, you will see behind the butterfly a bunch of black deposits. Spray a rag with brake clean and clean the bottom and top mating surfaces very well. Fixed.

 

https://youtu.be/5GEzoCowa4w