AkPrecision Posted January 1, 2015 Share Posted January 1, 2015 Ok so i have had this intermittent misfire which rocks the car sometimes but not everytime. Its been going on for about 2 months and on xmas night it rocked harder and longer than any time before then flashing cel and then it stayed on. Got code for cylinder 2 misfire. So i got brand new ngk double platinum plugs and all new hitachi coil packs. Put them in today and now runs like a champ. Previous owner put aftermarket coils and cheap plugs. Howevver after driving about 15 miles it started rocking a bit again then stopped. No cel yet. Went on another very short 2 mile drive and nothing happened. Could it be an injector? I just put fuel system cleaner in it this tank and that when it got real bad. Link to comment Share on other sites More sharing options...
AkPrecision Posted January 1, 2015 Author Share Posted January 1, 2015 Got flashing check engine light happened again Link to comment Share on other sites More sharing options...
jyeager Posted January 2, 2015 Share Posted January 2, 2015 Double check your coils and connections? If the root cause were fuel related, then you wouldn't have noticed it getting so much better once you changed plugs and coils. And you would have other codes thrown in addition to the miss fire code (such as O2 sensor and Catalyst). Did you have the codes read again to see if you are still getting the same cylinder misfiring? If it's the same one misfiring just to be sure I would swap that coil with another one and see if the misfire moves...just to determine whether you did or didn't get a faulty coil. Otherwise, I would start looking in to the possibility of an internal engine problem with that cylinder. Run a compression test on that cylinder in case you have a bent valve. Link to comment Share on other sites More sharing options...
fixinto Posted January 7, 2015 Share Posted January 7, 2015 (edited) Next time it happens, Find a place to stop, and shut off the engine, check the code (if you do not have a code reader i guess the nearest auto parts store will do) to see which cylinder and then pull that plug, see if it is wet and smells strong of fuel, if so, then the coil is not firing for whatever reason, I would probably check the wire harness where the number 2 coil plugs in to make sure there isn't a lose or interment connection to the coil. If the plug looks O.K. I would then think about the number 2 injector. As long as it is a single cylinder misfire code it makes life way easier on finding the problem. If the spark plug looks fine, and doesnt smell like fuel, and the plug in to the coil looks fine, i would probably follow the advice from above and do a quick switcha roo on the number 2 and 1 coil. If the problem stays with the number 2, then also as stated above it may be time for a compression check to see if you have a problem with one of the valves or something. I hope you get it lined out. Best of luck Pat Edited January 7, 2015 by fixinto Link to comment Share on other sites More sharing options...
AkPrecision Posted January 7, 2015 Author Share Posted January 7, 2015 Ok so i have been driving it to work and back everyday (only 4 miles) and it only does very small rocking every once in a while but is not throwing a code. I had the flashing check engine light again but then it shut off and there was no codes or pending codes. So im trying to drive it a lot to get check engine light. We went to my buddies shop on new years day and spent 3 hours messing with it. Did a fuel pressure check and both pressure readings were right on the money so it passed that. In the last 5 days it has only rocked maybe 5 or 6 times and for less than 3 seconds. Each time. Last tank i put fuel system and injector cleaner in and thats when the rocking got bad and check engine light went on. I had about 1/4 tank left and then we changed the packs and plugs. Then i put a half tank in and the rocking was bad once on the freeway right after leaving my buddies shop then barely at all after that. It may not be related but i thought it may be worth mentioning. Also it was idling at my buddies shop on and off fpr ten or fifteen minutes then for about an hour straight and it didnt rock once. Thank for all the help. I may try changing fuel pump or compression check but i really am trying to get the cel on again to see if its the same cylinder or not Link to comment Share on other sites More sharing options...
fixinto Posted January 8, 2015 Share Posted January 8, 2015 (edited) If you checked the fuel pressure and the rail read correctly, i wouldnt throw a fuel pump at it, its one of those things that its right or its not. Also if your fuel pressure were low, it would be a multi cylinder misfire more than likely, because your injectors are fed off a single rail per bank. The fuel pressure being off would starve all the injectors, not just the number 2. "just sayin" Remember also that you can stab your multi meter to the injectors and should get the same ohm reading plus or minus 5ish percent across the board. If you measure 3 and they are all around 1500 ohms, and you measure a forth and it is around 1100 ohms, or OL, or 100 ohms. there you have it. "just for the record i wasnt saying 1500 ohms is spec, it was just an example" Point being, there are several things you can do that are free, that will put you on the path to fixing the problem. I try everything to pin a problem down before i start throwing parts at it, because i found out a long time ago, that there are too many things that can cause the same symptoms and if you change everything it could be, until the problem goes away, it gets expensive in a hurry. Good Luck with getting her lined out Pat Edited January 8, 2015 by fixinto Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 8, 2015 Share Posted January 8, 2015 +1 on it not being the fuel pump. If it comes and goes, it's not a bent valve, a bad pump, or a compression issue. Those would make for a constant miss. This sounds electrical to me. You're ruled out the coil packs and the plugs by replacing them, so the problem must be between them and the ECU. I would check the electrical connections and wiring for the coil packs, looking for nicked insulation, blue copper, crud in the plugs, anything out of the ordinary that would explain lost spark. I guess it could be a vacuum leak on cylinder 2, but given that it acts up under load about the same as it does at idle, I don't think that's very likely. Link to comment Share on other sites More sharing options...
AkPrecision Posted January 14, 2015 Author Share Posted January 14, 2015 Thabks for the suggestions guys. I have been driving it regularly and the only time since my last post anything has happened is one tiny bump on the freeway after driving 40 miles then about halfway back it had one tiny misfire. Still trying to get cel to go off but it seems to be running good other than that Link to comment Share on other sites More sharing options...
fixinto Posted January 15, 2015 Share Posted January 15, 2015 thanks for the update, i was wonderin what ever came of the misfire case. im almost sure its going to be something goofy. is your VQ drive by wire? just curiuos. Also, there is a FSB about a "butterfly screw that backs out and causes bad joo joo to tops of cylinder and valves. hope nothing like that happend to yours. "probably not because if it did, it would be yet another one of those all the time things" not just random. Probably a connector or something. Anyways thanks for the update, if you ever nail it down im very curious have a good one Pat Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 15, 2015 Share Posted January 15, 2015 Yep, VQ is drive by wire. It was one of the things I hated about my dad's '03, and one of the things that went wrong. Link to comment Share on other sites More sharing options...
01Pathmaker Posted January 16, 2015 Share Posted January 16, 2015 My 01 vq35 is cable not drive by wire, did they change before they went to the r51 with the 4.0? Link to comment Share on other sites More sharing options...
AkPrecision Posted January 16, 2015 Author Share Posted January 16, 2015 The 01-02 is drive by wire. I believe 03-04 has electronic throttle body. Mine is drive by wire. I am now thinking it is either fuel pump or something electrical.could be a plug for coilpacks. Ill have to look closer. I still think there is a chance it could be the fuel pump i need to go on a longer trip than 4 miles to tell. I drive it everyday 4 miles and back to work. Runs great. But i am thinking it has only misfired after driving for a while or when im smashing around in it. I discovered a couple months ago the fuel filter was backwards for who knows how long so it may have made the pump work harder therefore maybe damaging it or the tube. Just a theory. But that's all I've been working on the while time...a theory lol Link to comment Share on other sites More sharing options...
Kingman Posted January 16, 2015 Share Posted January 16, 2015 Like Pat said a fuel pump doesn't make sense since it was a single cylinder misfire. And just because you replaced the coil pack does NOT mean it's ruled out. A sticky injector can be erratic as well. Link to comment Share on other sites More sharing options...
AkPrecision Posted January 16, 2015 Author Share Posted January 16, 2015 I was also thinking injector but thats last on the list. Looks like i have to remove the air box again and two manifolds to get to them Link to comment Share on other sites More sharing options...
AkPrecision Posted February 5, 2015 Author Share Posted February 5, 2015 Ok so finally after two weeks of not driving the pathy i get in and i finally get a check engine light. Code was cylinder two misfire. So im guessing injector. If it was a valve out would be a consistent problem right? Link to comment Share on other sites More sharing options...
AkPrecision Posted February 5, 2015 Author Share Posted February 5, 2015 Ok so finally after two weeks of not driving the pathy i get in and i finally get a check engine light. Code was cylinder two misfire. So im guessing injector. If it was a valve out would be a consistent problem right? Link to comment Share on other sites More sharing options...
Slartibartfast Posted February 5, 2015 Share Posted February 5, 2015 Yep, a bad valve is usually a consistent misfire. I have heard of valve guides coming loose on some Subaru engines and causing the valve to not seat properly, then sort itself out, then not seat right again (and I've seen one stuck wide open, zero compression) but I've never heard of a Nissan motor doing that. Sticking injector on #2 makes sense. You might try a fuel system cleaning before taking it out, on the off chance that fixes it, given how buried things are on the VQ. A backwards fuel filter probably didn't hurt anything, it's not like they have anti-drainback valves. The ones I've looked at blew through just as easily from either side. All I can figure is that the filter elements are designed stronger in the direction fuel is supposed to flow. Also, what's the distinction between drive-by-wire and electric throttle body? Both of them have the computer controlling the TB, right? Link to comment Share on other sites More sharing options...
AkPrecision Posted February 11, 2015 Author Share Posted February 11, 2015 Ok so i got a new injector from rock auto.it is an oem hitachi it was around 70 bucks. Just did a compression check on cylinder2 and compression is perfect. The plug did look white when i pulled it which would signify spark but no fuel so hopefully it is the injector.we will know soon Link to comment Share on other sites More sharing options...
fixinto Posted February 13, 2015 Share Posted February 13, 2015 cool thanks for the update, been following this to see if you get it lined out Link to comment Share on other sites More sharing options...
AkPrecision Posted February 14, 2015 Author Share Posted February 14, 2015 Ok everyone since this has been an intermittent problem and i drive less than 10 miles round trip a day to work and back its hard to say so early but the injector is in and i had driven it about 50 miles and let it idle for over an hour and so far no misfire. If i do get a misfire in the next month or so i will definitely be sure to post in this thread again and let everyone know. So far so good! On another note just got my ac springs and my 1" spacer from fluerys this week and hopefully going to throw it on this sunday Link to comment Share on other sites More sharing options...
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