What could cause idle misfire besides plugs?
Update 9/2/11
So here I am almost two weeks later basically right back where I started. Tonight I pulled out my stock fuel rail, stock FPR, and the FIC 1050s and threw in another stock rail and FPR along with some stock injectors. The end result is that I'm right back where I started. I can still hear and feel a small hiccup/msifire in the idle but it's not nearly as bad as it was with the 1050s so I'm going to stick with the stock injectors for now. After working on this issue almost every night for nearly two weeks here's what I've learned:
1. Even though one of the stock injectors had a broken tip, that was not the problem.
2. I now know how to install injectors but switching to larger injectors (FIC 1050s) made the problem worse and much more noticeable.
3. I now know how to disable and block off the EGR but that also did not fix the problem.
4. Putting in a different stock fuel rail and FPR did not fix the problem.
5. I could not find any vaccuum or boost leaks that were causing the problem.
6. Even though the idle was worse with the 1050s, in daily driving the car actually drove better with the 1050s than it did with the stock injectors. The car would go rich and nearly die when coming to a stop sometimes with the stock injectors. That problem went away after installing the 1050s. (Probably a tuning issue)
7. Tuning for larger injectors was a lot easier than I thought it would be.
I'll be sure to update the thread if and when I find a solution to the problem but at this point I'm done messing with it for at least a few days.
So here I am almost two weeks later basically right back where I started. Tonight I pulled out my stock fuel rail, stock FPR, and the FIC 1050s and threw in another stock rail and FPR along with some stock injectors. The end result is that I'm right back where I started. I can still hear and feel a small hiccup/msifire in the idle but it's not nearly as bad as it was with the 1050s so I'm going to stick with the stock injectors for now. After working on this issue almost every night for nearly two weeks here's what I've learned:
1. Even though one of the stock injectors had a broken tip, that was not the problem.
2. I now know how to install injectors but switching to larger injectors (FIC 1050s) made the problem worse and much more noticeable.
3. I now know how to disable and block off the EGR but that also did not fix the problem.
4. Putting in a different stock fuel rail and FPR did not fix the problem.
5. I could not find any vaccuum or boost leaks that were causing the problem.
6. Even though the idle was worse with the 1050s, in daily driving the car actually drove better with the 1050s than it did with the stock injectors. The car would go rich and nearly die when coming to a stop sometimes with the stock injectors. That problem went away after installing the 1050s. (Probably a tuning issue)
7. Tuning for larger injectors was a lot easier than I thought it would be.
I'll be sure to update the thread if and when I find a solution to the problem but at this point I'm done messing with it for at least a few days.
Last edited by Ian0611; Sep 2, 2011 at 12:00 AM.
OK this is really starting to drive me crazy!!! I can't win no matter what I do! I went back to stock injectors last night which helped smooth out the idle, drove the car to work today and it died on me at almost every stoplight!!
I had this problem before with stock injectors but it was never this bad, and I was able to make it go away (for the most part) by raising the ISCV tables. The part that gets me is that I went back to the very last ROM I had on the car before I put in the 1050s so I would've thought that it would run just like it did before the 1050s but I guess not. The only thing that's different is the EGR is now disabled and blocked off, but I highly doubt that that's what's causing the problem. Someone please help if you have any suggestions. This car is getting closer and closer to wearing a For Sale sign everyday!
I had this problem before with stock injectors but it was never this bad, and I was able to make it go away (for the most part) by raising the ISCV tables. The part that gets me is that I went back to the very last ROM I had on the car before I put in the 1050s so I would've thought that it would run just like it did before the 1050s but I guess not. The only thing that's different is the EGR is now disabled and blocked off, but I highly doubt that that's what's causing the problem. Someone please help if you have any suggestions. This car is getting closer and closer to wearing a For Sale sign everyday!
Last edited by Ian0611; Sep 2, 2011 at 11:57 PM.
I'm having some tuning nightmares with mine as well. It seems like sometimes my changes affect the car and sometimes they don't. A couple days ago my idle would be higher than normal, and restarting it would fix it. Happened a few times...
My idle does sometimes miss and I think something is broken because my ISCV idle settings are not having an effect on the car. Good luck with your search, don't give up. could a professional tune work it out? Im inches away from throwing everything I've learned and aspired to learn to get real, professional rom work.
also, can you post a video?
My idle does sometimes miss and I think something is broken because my ISCV idle settings are not having an effect on the car. Good luck with your search, don't give up. could a professional tune work it out? Im inches away from throwing everything I've learned and aspired to learn to get real, professional rom work.
also, can you post a video?
Last edited by prowakeskater; Sep 7, 2011 at 07:39 PM.
I'm having some tuning nightmares with mine as well. It seems like sometimes my changes affect the car and sometimes they don't. A couple days ago my idle would be higher than normal, and restarting it would fix it. Happened a few times...
My idle does sometimes miss and I think something is broken because my ISCV idle settings are not having an effect on the car. Good luck with your search, don't give up. could a professional tune work it out? Im inches away from throwing everything I've learned and aspired to learn to get real, professional rom work.
also, can you post a video?
My idle does sometimes miss and I think something is broken because my ISCV idle settings are not having an effect on the car. Good luck with your search, don't give up. could a professional tune work it out? Im inches away from throwing everything I've learned and aspired to learn to get real, professional rom work.
also, can you post a video?
dude im in the same boat as you..check your iac sensor i just found out mine is leaking alittle where it connects to the throttle body(the o-ring). but my idle is very ****ty to i have low vaccuum and alot of shaking at idle do you have that?im just gonna take the car in next week to make a professional look at it
Yeah I'm not sure when that will be now that I have a baby on the way. I've made some changes to the tune lately that seem to be helping but at the same time, some of the changes I've made shouldn't be necessary if everything is working properly.
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From: cherry point,nc
i have the same problem with mine right now, mine also tries to stall once the rpms drop from above 3500. i have already trouble shot the vac lines and cant seem to find a leak, one of my friends had this problem and it was his map. and the iridium plugs do not come pre gapped at .028 they are around .032 which causes a light misfire on near stock applications.
i have the same problem with mine right now, mine also tries to stall once the rpms drop from above 3500. i have already trouble shot the vac lines and cant seem to find a leak, one of my friends had this problem and it was his map. and the iridium plugs do not come pre gapped at .028 they are around .032 which causes a light misfire on near stock applications.
I made some changes to my injector latency tables and threw in some fuel injector cleaner and the problem isn't nearly as noticeable now. The odd thing about it is that I'm on stock injectors so there's really no reason (that I can think of) that my fuel trims would be off and I would need to run modified latencies unless there's something else wrong.
I made some changes to my injector latency tables and threw in some fuel injector cleaner and the problem isn't nearly as noticeable now. The odd thing about it is that I'm on stock injectors so there's really no reason (that I can think of) that my fuel trims would be off and I would need to run modified latencies unless there's something else wrong.
What injector cleaner did you use and how?