well no misfire yet... *knocks on wood* i told myself next time it misfires I will not be lazy and swap the injector....

Maybe it magically disspeared...

 

well misfire came back, I think I may have the solution. Checked the MAF gm/s and they are out of spec, @ idle it should be 2-6gm/s and mine is 1.95, and @ 2500rpm spec is 7-20somethign(i forget) gm/s and mine is 6.98.. both barely out of spec but my MAF is dying.

I will replace that and report back.. athenG maybe u should investigate yours as well since you have the same problem as me.

 

I just replaced my MAF about 2-3 months ago (mine was used but supposed to come from a low mile car) but come to think of it, my misfire has gotten worst after the replacement. I used to get misfire maybe once every 1-1.5 a month but now I get them every 5-8 startup, I reset my ECU many times and just swapped my coils today so I'm waiting if the error comes back...

I replaced my MAF coz I thought my old MAF was going bad, when I borrowed Glex25's extra MAF all the error went away and I had it for about 3 weeks...

 

hmm you should test it so you can rule it out. Probably do a compression test too. Can you get your hands on a nissan consult II so you can monitor the maf?

 

I'm thinking it maybe my injector is clogged or something.. The problem all started in the Winter, I had to add more fuel below 1500rpm just to get it to idle around 14.7. I just replaced all my spark plugs, and swap the coil, and cleaned my Air Filter and MAF sensor. I haven't gotten the P0302 error but I do get P0300 more often now.. I literally get the P0300 every 4-5 startup, I get them mainly in Hotstart

Like I said, I had to add more fuel below 1500rpm just to get the right A/F at idle but at WOT (under Utec control) my tune is still the same and never had to add any fuel. Nothing really got changed so I'm concern why my fuel scaling was off, mainly in the idle rpm range only..

 

worth checking alternator output at idle - I had a nasty misfire that I could not get rid of at all - turned out the alternator bracket was loose, and at idle, I was not getting a great charge at all

 

/\ thanks, my battery went dead twice this winter and I was not sure if my battery is going bad or it is not getting enough charge. I do noticed though that it is harder to start my car lately, usually my car fire up real quick in just a click/crank but lately it takes longer to start the car.

 

hopefully that is it...at least it will give you something to rule out if its not

may also want to load test the battery as well (I think places like Autozone, etc might do it for you if you don't have access to the equipment yourself). My stock battery lasted from fall 03 when I got the car to I think winter 2007 - about 40k miles before it just gave up. I ended up replacing it with another OE Nissan one as they are inexpensive

 

Yeah, I'm going to Nissan tomorrow and have them check my MAF/02 Sensor/Alternator/Battery and maybe have them raise my idle too.. If those things all turn out ok then it's time to upgrade my injectors..

By the way I just had my Oil Analysis a couple of months back and everything is ok and I dont have any oil consumption issue.. so I wont jump on the compression issue yet but I'm not totally rulling it out too..

 

let us know what you find

 

I guess my MAF is ok coz at idle I get 2.8-3.4 g/s and about 11.x at 2700rpm.. My Alternator and battery is fine so now I'm back to square one My friend who's a Nissan Tech told me my car sound/feel like it is misfiring more than 2 cylinder but I'm not getting an error at that time. My car sometimes will shake and when the rpm dip below 750rpm my A/F in one bank (sometimes both) will go real lean, It will go 18:1-19:1 for a couple of seconds.

Didn't really get a chance to test the 02 sensor but my other option is replace all Coil Pack or injectors. I'm still getting the P0302 error even after swapping that coil to another cylinder, but because I still get a P0300, he's telling me to just replace all coz it is hard to pin point which other coil pack is going bad.

I'm leaning on replacing my injector though but it just drives me crazy coz at cruising speed I get 14.1:1 - 14.7:1 and at WOT I get 11.3-11.6 which is spot on.... The car feels great though when I'm driving.. Either way it will be $600 to replace all coil pack and about the same price for injector, and if I guess wrong then that is $1200+ for both or it could be totally something else that needed to be replaced... lol

My misfire has subside now that it is a little warmer here in NY.. I might wait a couple of more weeks and see how it respond on warmer weather (thank God Spring is around the corner).

Keep me updated on you MAF replacement.

Edit:
By the way I dont have any CAT and I'm using a non-fouler with my test pipe..

 

Let me know if you need anything to help you troubleshoot.
I got 6 coilpacks in my garage now and I'm installing the DW and CJM tomorrow. I will have my APS injectors and you know my car ran perfect
and I still have that MAF.

 

did they check your A/F Alpha? Gotta see how they look, and compare banks 1 and 2, they should be between 91%-109%, lower being richer. That could give you an idea if its A/F sensor... yea your MAF are in spec...

I dont think you need to replace all of your coils... thats pricy, and probably not going to fix it, especially if you swapped and the misfire stays on the same cylinder.

Are you losing coolant by chance?

Looks like its time to pull your injector and swap it with another... see if the misfire moves. If you swap all your coils and injectors I think thats a waste of money.

 

no need to spend $600 on coils that's for sure...the dealer markup is insane on them - let us know if you need any, we stock them

 

I was gonna send you a PM the other night to borrow your MAF again to eliminate the MAF problem coz I'm pretty sure I was fine when used yours for 2 weeks, but then again I didnt really drive that much. I didnt want to bother you again so I just went and get it check but didnt really got a clear answer..lol I'll PM you regarding the injectors...


I'm not loosing any coolant, I couldn't remember but I know I saw something 9x % on the 02 sensor somewhere. My friend just dont want to jump on the 02 sensor yet with my misfire. I was thinking of checking the injector and make sure they are seated right and make sure there is no leak but it is still damn cold to work outside.

 

yea check the injectors before you buy anything, just to make sure.

 

No need to drop money on new injectors. If you have a decent amount of miles on them a cheap way to trouble shoot is have us clean and test them.

Shoot me an email if you need help Mike@DeatschWerks.com

 

I was thinking of having them tested or cleaned but I needed to upgrade to a bigger injector anyways..

Update,
I did a full ECU reset but this time I let the battery disconnected for 6hrs (before I only do 10mins while pressing on the break pedal) and did a minor tweak on my 0 column in Utec and so far no Misfire!!! I have been driving all weekend long and not a single misfire. This is far better coz before I get them every day or every 4-5 startup.

When I get a free time I'll have my injector tested because I'm still concern why all of a sudden I needed to add fuel on my tune with nothing changed on my car.

 

just wondering, the car is still running ok?

 

have you guys checked in the open loop fueling portion of your paramaters on the utec? there is an area where you can input the size of injector running and the stock injectors size for scaling of the injectors.