Ok so I have an 03 greddy TT Z. It only has 34,xxx on it so its in good shape. But sometimes randomly every once in awhile it seems that the engine is misfiring out of a cylinder for a little amount of time and then corrects itself. I have no idea what it's from. My first guess was maybe there was a little moisture in the gas/cylinder? Or could it be bad spark plugs? Maybe needs tune? Please let me know what you guys think it could be or if you have experienced this issue, Thanks!!

 

i would change the spark plugs and go from there see if that fixes the problem. How many miles on the current spark plugs?

 

ok i'll try that and hope thats it. Probably 15,000 or so

 

yeah definitely try changing them.

 

ok thanks for help!

 

do you get a cel? you will know the car is actively misfiring if you have a cel and it start blinking.

 

Im pretty sure it's not connected anymore. The last guy disconnected it i'm guessing.

 

so you cant pull any codes anymore? the CEL light is over the CANbus so if its not working, nothing in the cluster would work.
You just cant 'unplug' it

 

you can take the bulbs out so it doesnt light up anymore...

 

O really? Well the cel doesn't turn on at all so maybe they took out the bulb. I'm gonna try to test the codes tonight.

 

maybe someone took the bulb out to prevent you from thinking that the CEL was on... someone did that to my friend when he bought his car... they were hiding the whole evap system was messed up and the engine eventually blew on him.

 

take it to a stealership or vatozone and see if it is throwing a code though if its a misfire that is only occasionally happening then the CEL won't be on all the time.

 

Frick that's scary- especially for guys who are driving used cars and going FI...

Guess we do need to pay close attention to our startups and manual ECU resets!

 

isnt the 'bulb" a soldered in LED?

so when you start the car your CEL doesnt illiminate?

 

Like he said, when you start your car, see if the light comes on for a second.

 

Ok problem solved! It was the spark plugs. The old ones had a lot of carbon build up. I changed them out and now it runs better than before! Thanks for the feedback.

 

Glad it turned out to be something so simple.

 

What are you tuned with? If with osiris, some tuners turn off the DTC codes for Misfires. Just keep that in mind.

Glad you got it working again

 

Sounds like you should get a good retune, plugs don't just foul up that bad with a properly running engine.

 

Ya I know it can use a tune. It's running a little rich. I haven't tuned it since I got it about 10k miles ago. It has the greddy emanage which I've heard isn't that great. But I'm posting it up soon FS/FT.