DjDannyXL

All my Cyls are misfiring. I just changed all the spark plugs and put in some NGKs and that didn't solve nothing. Plz help. what can cause all cylinders to be misfiring. I had the cat replaced because I had P0420, 2 days later the CEL went on again
and I thought the computer was just not picking up the new cat right so I didn't get it check. I let my car sit for one day and the next day I turned it on and my exhaust was shaking violently. other than an exhaust my car is stock. it has 81,850 miles.
Any help??

Check Engine Light also blinks when driving around but not when in idle

Here's a small clip I took of how my exhaust sounds

Martyr03

iTrader: (2)

did you make sure all of your plug gaps were correct

DjDannyXL

if the gap is supposed to be 0.44 then yes

AnotherDude

iTrader: (1)

Next step would be coil packs I would think. Still doesn't solve why your exhaust shakes so violently though. Which catalytic converter did you have swapped out? There is one on the header and another on the mid pipe.

And you're sure your exhaust is stock? your axleback looks a bit big....

DjDannyXL

the one on the header. why would all the coil packs go out at the same time though? same with the spark plugs. what can cause all the cylinders to misfire at the same time

my06tc

iTrader: (2)

you change the cat on the exhaust manifold...are you sure,its not a easy task you know,better off getting a new exhaust manifold......the one of the midpipe is the one to be concerned about..check your compression and clean the maf sensor

DjDannyXL

The one on the midpipe doesnt get picked up by tue computer. That one was taken out when i gOt my exhaust put in. But that was like a month ago.

XPRESSCION

I had the shaking exhaust problem on the old tC. I never really fixed it: I knew good throttle body clean would do it. I never got the chance to do it. After my 234k driven; I will tell you the exhaust shake was starting point when other things that started this list of crap happening down the road.

Rough idling, motor stalling, poor acceleration, mpg dropping, burning oil, and eventually which made me trade it in: transmission slipping on hills.

I didn't change out the coils until last December. They were FRIED! Yeah, I did change out the plugs every 50k.

TotalChaos

Are all the coils plugs in the correct cylinder? What catalytic converter did you use? OEM? Aftermarket? What brand? Did the CEL codes appear before or after plugs were changed? It sounds like after but just confirming.

DjDannyXL

Not sure of the brand. Might be magnaflow since thats what the shop i got it done at has in stock. The CEL codes were on b4 i changed the plugs. The plugs were my first step in trying to fix the problem. They were pretty burnt up but that didnt fix anything. I've seen way worse plugs than mine though

simplyred

Maybe it is a simple fix.... by chance did you reset the ECU? Let it sit dead for 5 minutes or so and then crank and let idle for 5 - 10 minutes more. Also, did the shop hook all the sencors back up? Correctly?

DjDannyXL

By resetting the ecu do u mean reset the CEL light? If so then yes. If not then sorry for aounding dumb as i dont know much about this stuff. Havent checked if they hooked up the sensors correctly. But its not throwing any other codes besides the misfires. P0420 went away and hasnt came back and ive driven it more than 400 miles already

jacob81

Unhook your negative battery cable for about 10 mins, reconnect it, let it idle for about 10 mins, drive it easy for about 50 miles and see if the CEL comes back on or it continues to misfire.

DjDannyXL

thanks for the advice but i got it fixed already. it was a bad coil pack. i took it to autozone and their obd scanner said all cyls were misfiring. had a mechanic take a look and it was just a coil pack. i was gonna check that next after the spark plugs but since autozone lied to me i assumed just one coil pack couldnt make all cylinders to misfire

Sciontc0922

Hey men i got the same problem but i havent fix it yet, wat u exactly do to fix ur car men thanks

DjDannyXL

i havent fixed it yet. i changed one of my coil packs which made it better but theres still 3 misfires. i tried changing another coil pack but nothing happened after that.

you should try cleaning your throttle body. i havent done it but its a simple task. let me know if it worked or not if you try it

jacob81

Maybe primary O2 sensor or possible mass air flow problem. I would also suggest running different plugs since this started after you changed plugs correct?

DjDannyXL

No. I tried changing the plugs after it started misfiring

That_Kid_Ju

Have you checked your injectors? Are you getting any other CEL codes with the misfires? Have you done a compression test?