3vo|3oost

I have been having some issues with my EVO8 cylinder 4 misfiring. While idling I can hear a sort of popping/missing noise like one cylinder isnt getting enough spark or fuel or something. I just recently replaced the spark plugs with the NGK laser iridium ones (i didnt adjust the gap, but checked them all were .024) thinking that was the problem, but still check engine light keeps coming on at least every other week. I was thinking that if it was a coil pack that was bad it would be 2 cylinders misfiring instead of just 1, and the only other thing I can think of it would be a bad spark plug wire or a bad fuel injector or dirty air filter?

The other strange thing is that under load/boost it does not misfire at all and runs smooth. Thanks and much appreciation to anyone who can offer me suggestions!

Aftermarket parts I have are full 3" exhaust no cats with atmospheric O2 dump tube housing, full Injen Intake and hard pipping, boost controller set around 20psi. (no tune, maybe that is my issue?)

03evo8gsr

iTrader: (5)

mine used to come on every 5 min driving or on idle. i had this issue about 3 years ago, i ran one step colder plugs. that helped a bit. than i chanage my ecu rom to an 05. no more missfires for me.

3vo|3oost

03evo8gsr thanks for the reply, I was thinking the same thing with the one step colder plugs. I might try to order a set to see if it helps, but what concerns me the most is the mis/pop noise at idle because it sounds terrible. (kinda sounds like one cylinder isnt firing at all, but under load/boost its fine which is super confusing) I guess I need to just buy a Tatrix cable and start trying to figure out this tuning stuff :-/

Maybe I can use the tuning software adjust the idle?

If anyone has any other ideas please let me know, thanks!

blacktab420

iTrader: (12)

My IX MR does the same fu&%?#&* thing . I have a new set of oem spark plugs gapped at .022 . Had a lot of random P0300 for months but it turned to a P0304 couple of week ago. Switched the coil pack and P0304 poped up again. Switched my injector 3 and 4 and now i have P0300 again today.

I will make a video of the idle noise tomorow . I is a very annoying sound, like it is always missing a little bit randomly when the car is warm.

Notch

Swap coil packs between 1 and 4 and swap injectors between 2 and 4 and see if the problem persists. Take a look at the plug in cylinder 4 for any differences between the other plugs.

3vo|3oost

Correct me if im wrong, but cylinder 4 the furthest one away from the timing belt right?

blacktab420

iTrader: (12)

you are right

3vo|3oost

Ill took out all the spark plugs and couldnt tell any difference between cylinder 4 and the rest of them... but I ran out of time so next time im gonna try to swap the coil packs and injectors to see if that helps... Does anybody know if you can use tuning software to adjust a rough idle? My wideband says 14.7 at idle, but it runs super rich so shouldnt it be at like 15.2 or something closer to 15 A/F ratio?

kwanza

What is the code for the check engine light?

3vo|3oost

The code im getting is P0304 which refers to cylinder 4 misfire (the P0300 code in general refers to the misfiring of a cylinder and the 1-4 at the end refers to which cylinder it is)

kwanza

Maybe a bad injector?

Found this:

https://www.evolutionm.net/forums/ec...inder-4-a.html

3vo|3oost

thanks kwanza thats some good info! Tonight I am going to swap injector #4 with injector #2 and see if the code follows. The code only comes on intermittently about once every week or two, so once I swap the injector then I will have to wait and see if it shows up as a P03002 instead of a P0304 code... I will post what I find out.

dastallion951

simple thing to check since uve done plugs, check and make sure ur injector connectors are securely fastened, could be loosening up due clip not installed right or missing. Now when you pulled your # 4 plug, did it look wet like it was doused with fuel, or really dark and black like running rich? make sure when you reinstall the plugs and wires, make sure the boots for the ignition coils, as well as the other two plug wires have di electric grease put in them for a better fire, and make sure the boots and wires arent cracked or fraying...that can have somethin to do with it too.
good luck

3vo|3oost

Last night I swapped injector #4 with injector #2, but after I started the car again it was leaking quite a bit of fuel from #4. I took it back apart and noticed that the #4 O-ring on the top of the injector got slightly shaved off on one side, but still looked ok enough to put back together so I cleaned it up best I could and put it back together again. Started car again and no leaks this time... I hope the O-ring holds up, but I drove to work and back home with no leaks so I think its good to go.

Now I am waiting to see if the code pops up again if it is #2 instead of #4 then I know the injector is bad... the code pops up intermittently so it could take a day or a week I dont know. Thanks for all the help guys! I will post on here when the code comes back on.

If it is a faulty injector my only choice will be to upgrade! =) Any sugestions on CC injector sizes? I want to upgrade my stock turbo eventually, but nothing straight race since its my daily driver it needs to be streetable.

dastallion951

id say go minimum of 1000 to 1200cc injectors, that way if you decide on e85 or anything you can run it on stock turbo or aftermarket down the road.