so i changed the spark plugs today for the second time (using ngk bkr7e also for the second time), but now i'm getting a p0300, p0302, and p0304 constantly flashing cel during idle. the idle is very rough and causes the car to shake while misfiring very badly. i re-tightened all the spark plugs and coil packs and the problem still comes up. is there anything i'm missing?

since only even-numbered codes 302 and 304 (not 301 or 303) came up, i'm assuming the problem is only on one of the sides (driver or passenger) of the motor, but im not sure which. the car is heavily modded, but was running perfectly with the exact same spark plugs just before i swapped them out for new ones. any help is appreciated.

-marc

 

i dont know if you figured out the problem yet, but when i did my spark plugs, one of the coilpack's wiring got disconnected and so the engine was running on basically 3 cylinders and had the same issue. Check to make sure all wiring is connected to the coilpacks.

 

did you try getting the stock plugs and putting them in?

 

P0300 = Random Misfire
P0302 = Cylinder 2 Misfire
P0304 = Cylinder 4 Misfire

Cylinders 2 & 4 are on the driver's side.

The boots may not be seated on the spark plugs correctly or the spark plugs are not gapped right. As was stated previously, it's also possible the wiring connectors for the coil packs are loose.

Good luck and let us know what happens.

 

I'm betting you put the packs back in the wrong order. I did the same thing the first time I did plugs and had the exact same symptoms as you. I remember putting them in by length and location. IE: the shorter one in the back plug thats closer, and the longer in the front plug thats farther away. Seems to make sense right, nope. Lumpy idle.

If the above code readings are correct...switch the packs around on the drivers side. I bet it will go away.

 

That's easy to check - the white connector goes on the front one.

Like this:

 

hey thanks for the responses guys it really gave me some motivation to get off my *** and get this thing resolved. i finally got some time to work on the car today...

i wasn't able to try puttin in the stock set of plugs, but i figured it woouldn't make a difference because rite now, im troubleshooting using the plugs that were in the car when it was tuned for mods.

took out all the coil packs, disconnected and cleaned the electrical connectors...no help. i still get the flashing CEL at idle (with backfires), but now my APv1 can't pull the codes! i called in to cobb tech support and they told me to take it to autozone to get the code pulled...odd

im about too go out and try switchin the electrical connectors on the driver's side coil packs. i know the white connector goes towards the front of the car on the passenger side, but is it the same for the driver side? rite now my driver's side coil packs have the white connector towards the back, and black connector towards the front. i don't see how they could've gotten switched because i didn't disconnect the coil packs from the connectors when i did the spark plug change.

-marc

edit: im not sure if this matters or not, but when switching the coil packs, can i just switch the connectors? should i just switch the actual coil pack with the connector? <-hope this makes sense

 

White goes in the fornt on both sides. You probably switched the whole boot.

 

u guys were definitely right. switched around the boots on the driver's side...and the worst thing is i don't even remember doing it. thanks for the help all