Hey guys, so about 2 weeks ago i had a misfire cylinder 6 p0306 code. I swapped the coil with #2 but got the same cylinder 6 misfire code a few days later. It seems to only throw the code on cold starts, i dont even notice a miss when the code is thrown, which is very random, and it runs fine otherwise. So i figured the plug might be bad so i replaced all 6, but today i got a missfire again on cylinder 6...



Comprssion test is my next order of business. Hopefully i have compression Anyone heard of this issue by chance? :/

 

did you check the plugs (condition and gap)? Double check the plenum bolts to ensure everything is torqued down? How many miles on your setup? What injectors are you running?

 

Thanks for the reply.

The plug on cylinder 6 had 2 thin black lines on the porcelain, i thought they could have been cracks so i replaced them but otherwise it looked fine.

I will check the plenum bolts, thanks for the idea, ill spray some carb cleaner around and see if anything happens.

Ive got 68k on the motor, about 15k boosted.

Thanks again,
Aaron

 

If you've got injectors that needed any sort of splicing, check those connetions, make sure there are crimps or anything. Can always try a bottle of Techron too, just in case you've got an injector that is hanging up a bit or something...easy and cheap enough that it's worth a shot as well. These types of things can sometimes be a pain to track down (I went through it on my car last fall so I know!), and often its the process of elimination that reveals them.

 

I have the same problem but always on cyl 2.. It only happen to me on cold start or when I'm lazy on the clutch and my car dies and start the car again. I have always thought that misfire with colder plugs, bigger injector are normal so I didn't bother going crazy with it. My misfire get worst when my plugs are close to 10K miles and usually ok when they are new.

 

Odd.... Well i have deutschwerks injetors so i didnt splice... Its odd that this would happen now after so many miles... Ill check compression and check for vaccum leaks, but i would assume low compression would be noticable during driving... Maybe a vaccum leak...

thanks for the suggestions

 

Has it done it since you replaced the plug?

 

Yes it did. I was planning to do a little more diagnostic today after work but its too busy. Tommorow hopefully.

 

Maybe injector went bad...

 

similar story. switch plugs-didn't help. then swaped coil pack and a can of fuel system cleaner. and now just get random misfires no spec. cylinder. I've been running injector cleaner last 2 tanks. word on the street is the vq injectors clog really easily. ill let u know if it helps. gl its really annoying

 

If you suspect its the injectors you can send them to DeatschWerks for flow testing.

-George
GT Motorsports

 

LOL@Deathwerks!!

 

thanks for the advice guys, im thinking its injector too. Havent had a chance to do a compression test yet, but probably thursday I will do that, and if that checks out I will swap my #6 injector with another one and see if the misfire moves.

Im thinking the compression should be fine, otherwise I would most likely be running like **** and have a miss at other times other than cold starts @ idle.

 

LOL that was actually a typo, it was late as you can see

I am actually a big supporter of DW injectors, can't beat them for the price, especially since they are manufactured by Denso.

-George
GT Motorsports

 

George you see many deatchwerks injectors hanging up? Only 15k miles on them... :|

 

Never hand an issue with the Denso DW injectors.

I doubt it is the injector, but not impossible, let us know what you find.

-George
GT Motorsports

 

im running out of options, either injector or something much worse like a valve or something lol...

It drives just fine, if I clear the code and drive it, it will not miss, only when its first started and idling...

 

Any idea what the resistance specs are for the DW injectors? Or should they be the same as the OEM specs?

 

So you get this every day? I thought you said random only...

 

Yea its pretty random, maybe one in 4 starts over the past 2 weeks or so.