Sunday night on the way to my friends house, I was just testing my spool since I just fixed my boost leak and fixed my cracked manifold, so I was checking out my spool. Its alot better now. But, 10 miles down the road when Im just crusing the car feels like its missing now. Well I figured I was about to blow an intercooler pipe. But I didnt, but I kept driving crusiing like a grandma to my friends. I eventually check everything and it was fine.

Long story short. I changed the plugs for new iridium bkr7ex-11 one step colder and then gapped them to 35ish since i needed 2 step colder but, noone around offers them. But, my mis fire continues.

I also rewired my crank sensor on my f/ic since that was a code i got and now that code is gone and not showing up. But, Im still having my mis. Now Im lead to believe it is a coil pack problem.


So here are my symtons: I start the car sometimes it will idle to 1000 then drop and die, and other time it will idle up to 1000 then drop to 400 but jump back up. and idle around 900. When I pull off in 1st it misses horribly and puts along, then same thing in 2nd. Then after Ive driven for a lil while it fells less prone to miss cuhz its not as noticeable but, if i go full throttle the power just isnt there. Ive been thinking its about to blow up because its not pulling timing. But, I fixed that problem and now its still missing. So, I dont know.

All this is happen even after i changed the plugs and got them gapped right..

 

I got my obd II scanned and its gettin mis fires on every last cylinder..

 

i was gonna say gap but you checked it.. mine had the same problem because the gaps were slightly off.

 

Well say im on 10psi and i was forced to buy one step colder plugs instead of the two step colder plugs im supposed to have. What should they be gapped to.. i ran them for a few hours on the 44 gap on them they come with. but gapped them down between 34-35. But problem still continues.. I just dont know.. Ill try 30 next. but im scared to go too far with the gap and have to open up the gap and mess up the iridum tips.. since i heard they are soo easy to damage,,

 

yeah they are.. but if you are only making 200-300whp one step colder is fine.. higher than that then you step into the 2 step colder world.

 

So should I leave the plugs gapped at what they come as. Or bring them in closer.

 

dezod said 35 is good so thats where mine are at. i'd say you are good right there.

 

the misfire is on only one cylinder? or on all cylinders?

 

its on all cylinders...

 

misfire on all cylinders could be a fuel problem, check fuel pressure and check to make sure none of your coils are cracked

 

I got rc 550cc so they required new clips. I wired them up and soldered them. Ill check them tomorrow.. and also i broke a stud on my block that you bolt the manifold on so i got a pretty good leak right there.. That could be making me run lean. I will post up pics of my plugs that I replaced yesterday.. They have white spots.

 

exhaust manifold? intake manifold? having a air leak causing you to run lean could def. be causing that misfire, I'd get that fixed and go from there

 

1. what type of engine management are you running (sorry if i missed this somewhere) EDIT: NEVERMIND, AEM FIC

2. what are your AFRs?

i have misfires on all cylinders too, but that's because my tune is way off and i'm running a little lean. check your AFRs and let us know

 

im gonna say that huge exhaust leak is your problem and causing the mis firing.

 

It could be a coil pack but its sound like your plugs just aren't delivering spark correctly. Put the stock plugs back for now see if u still misfire then try and get the 2 step colder that u need and lower your booost to like 6-7 just for now to be safe.

 

Well it sounds like it is miss firing even at idle. What is the AFR at idle?? sounds like it is either lean or pig rich but if it is rich you should be able to smell the gas in the exhaust. Also miss firing on all cylinders probably means all the coil packs are still good and the problem is somewhere else. Fix the exhaust leak ASAP so you can eliminate that as a possible cause of the problem.

 

ok.. will try and get a new stud tomorrow..

 

Ok. I finally got the car back to 100%. It was the stud causing the problems.. Now car is ready to get new stuff and go on 15 lbs.

 

same problem here, but it happens every time my car hit a bump on the road or some like that, turn the engine off for couple minutes then turn it back on, it runs well! guys have any ideas?

 

do you have a misfire evertime yo hit a bump? or does the car cut out? a friend of mine's mazda would cut out over bumps, and we figured out the battery was grounding out against the firewall cause the tie down wasn't secure enough, if it's misfiring over bumps I have NO IDEA, lol