Hey all,

My new 2.4 has ran awesome, until I changed the spark plugs yesterday, put in NGK Iridiums.......ever since its been hard to start, and idles ROUGH and sometimes dies........so I put my other plugs in, same thing, then went and bought another brand of plugs, same thing, so I went and got 2 extra 2.4 IDI covers and tried all 3, same problem..........I cant figure it out..............it ran perfectly fine until I changed the spark plugs, now it runs like @!#$.......no matter what brand of plug I put in, or anything, DEPSERATELY NEED HELP!!!

So far I have tried several IDI covers(the 2.4 Twin Cam cover), tried every brand of spark plugs, tried new Camshaft sensor, new MAP sensor and checked the computer to make sure it wasnt corroded, and still runs like @!#$.......I cant figure it out

Stupid question, but are you sure they're all seated properly? I would check them all... because if even one isn't, your car's gonna run like @!#$ because your not running on all cylinders. Also, maybe check the spark plug wires out... maybe you've got one hooked up wrong or maybe you'll need news ones?

those 2.4 are also comen for leaking injectors

check that you connected spark plug wires propertly, i had it happen to me as well when i was installing exact same plugs. the wires should be matching each individual plug in order.

take off your idi cover and check all your boots...make sure the spring inside each boot isn't corroded...you should change these anyways, check your spark plug gap, check your wires going to the idi, make sure there not cracked, or damaged, and i might be wrong but if you change your cam sensor, you might have to do a re-learn for it, looks like your were messing around alot so i would go over everything and make sure nothing is broken, and everything is right.



"If you have no clue what's going on... STFU!"

First off all there arent any Plug wires on a LD9

Before you started changing every part you could see you should have tried fixing and diagnose what you have

I would start by checking the GAP of the plugs

Then make sure all your springs are seating properly on the spark plugs

Are you getting an engine light?

What brand of NGK are you using are you sure they are the right ones for the LD9?

Hey yes Greg reccommended the NGK Iridium to me, so I got them, and ever since I put them in car has ran like @!#$ no matter what I do......yes, I have 3 different IDI covers and checked each cover carefully and made sure the boot springs are in good shape and I make sure they are seated properly on the plug, when I start the car I have to hold the gas pedal down and its smokes black and REAKS like gas big time and idles rough, then when I start driving it misfires every so often, not a lot when its running. I have no engine light, its really frustrating me!!!

get rid of the NGK and go back to acdelco the LD9 motors dont like any other plug other then the delcos

I got champions in right now, I went to canadian tire, they have Delco plugs but believe it or not they dont sell the ones for the LD9

get rid of the champions the only thing they work good in are dodges and my advise id try the boots and springs make sure everything is seating right like every 1 else has said

^^ i told him Champions ONLY work in Dodge LOL

i had NGK Iradiums in my old 2.4 for over 150,000kms worked great/


its the damn Sensor that attaches to the Throttle body by a rubber hose..........if that is messed the car will run like poop and pig rich..........

check your map sensor and the hose running too it. On my girlfriends car the hose running to it had rotted away and it ran like crap and misfired.

Already checked the Map sensor, its fine and the hose is in good condition. But for the hell of it I went and got another one with a different hose and tried it, still nothing running better.

try putting your original stock plugs back in???

not sure if this was already answered but did you double check the gap on your plugs??

I never check the gap on plugs, never have and they always run fine, the BOSCH ones you dont have to, its in their design, but I have 4 brand new sets of plugs and i dont think they are all not gapped, the factory that makes them usually does.....I have no idea how to gap them anyways. I think maybe its a bad fuel injector?

when we installed my supercharger I had to gap my plugs.

is your check engine light on???? if so probably a good idea to get it scanned. If you post up a code I can run it through the SI database.

You should always gap your plugs no matter what the package says

Iridiums run fine in LD9s i have never had an issue

Are you throwing any codes?

No engine light is on, I have my own OBDII scanner, I unplugged sensors while the engine was running (Camshaft sensor, and map sensor) and reconnected them so those are the only codes I got since I unplugged them when the car was on...................no other codes. Im going to try to get a camera to take a short video for you guys, I am on the verge of giving up and getting rid of it, I love my car but its really bothering me. I even had it taken to a mechanic and he could not find the problem.

Darren MacDonald wrote:You should always gap your plugs no matter what the package says

Iridiums run fine in LD9s i have never had an issue

Are you throwing any codes?

That's correct. Different cars use a different gap, so you always have to set it for your particular needs.

I'd avoid any of the gimmicky plugs. It's been a common theme here that the AC Delco's work best in these cars.

like I said in my first post^^

its worth a shot anyways, I have seen NGK in our cars screw up before and as soon as they went back to the ac delco ones and reset the computer by leaving the battery disconnected for a bit the car ran normal

Robbie Pellow wrote:No engine light is on, I have my own OBDII scanner, I unplugged sensors while the engine was running (Camshaft sensor, and map sensor) and reconnected them so those are the only codes I got since I unplugged them when the car was on...................no other codes. Im going to try to get a camera to take a short video for you guys, I am on the verge of giving up and getting rid of it, I love my car but its really bothering me. I even had it taken to a mechanic and he could not find the problem.

try a different mechanic, or if your desperate a dealership.

I am currently laid off so dont have a lot of money, trying to avoid the Stealership. What can I do how can I find out if its a bad injector?

Update, i got a new set of NGK Iridiums, and spaced them to 0.060 and tried, still runs like @!#$. could it be fuel pump dying? Injectors? Timing is off, i doubt the timing can just go off, especially on chain driven timing....but could be wrong, this is frustrating as hell no one can figure it out!!!!

maybe hit the wreckers and borrow some injectors then =)

they easy to install yourself?