Have you figured out a solution to this problem? As I am in the same boat...

 

cam/crank sensors?

 

No not really. I tried running some fuel system cleaner through it and while the car does seem to be performing better and is getting better mpg , the issue with hiccups/misfires at idle still persist. I'm starting to lean towards it being a vacuum leak but I don't really know how to check for one. Do you just try to go through and look for all the vacuum lines and see if any of them are off or look bad?? IDK. I'm also thinking it could be related to the hole in the gasket on my O2 housing and I'm planning on fixing that soon but it's probably going to be at least a couple more weeks before I do. I'll definitely update once I get this figured out though.

 

^^^ there ya go man, an exhaust leak on your 02 housing, your primary 02 sensor is there, so any air can leak into the exhaust leak meaning it gives that sensor false readings, an exhaust leak will do similar symptoms to a vacuum leak. theyll make the car run more lean, get it fixed and then see if its fixed.

 

Yeah the only reason why I question whether or not that's causing the problem is because I've patched the hole two different times and I don't recall noticing much of a difference. I suppose it's possible the gasket has more than one leak. Either way, it's getting fixed when I do my turbo swap so we shall soon see

 

Update:

So for no particular reason I let my car get really low on gas before I filled up this week. Normally I fill up when it's between a 1/2 and 1/4 but this time I was probably down around 1/8, maybe even a little lower. I noticed that the last day or two when it was below 1/4 the idle was a lot rougher and the misfire/hiccups were even more noticeable. I filled up yesterday and let it idle for a minute when I got home last night and the problem was still there but seemed better than before I filled up. So now I have a couple more possible causes: fuel pump, fuel filter, injector. Any thoughts guys??

 

Are you using the factory O2 housing gasket? Those aftermarket ones always burnout and leak.

 

UPDATE

Monday 8/8/11- Well I got the turbo swap done and all of the gaskets changed out but didn't really notice a difference at first. However, while I was working on retuning the boost I noticed that I had set my WGDC below 2K to 110 for some reason, so for no apparent reason I decided to set it back to 100 and afterwards the hiccups/misfires were almost completely gone.

Fast forward to today (Wed. 8/10/11)- Filled the car up at a different gas station out of town, started the car up, and right away it started idling really funny and misfiring. However, the misfiring this time was much more noticeable than it ever was before. I let it idle for a minute or two and recorded some logs of it since I happen to have my laptop with me. I noticed that the fuel trims seemed to be jumping around a lot more than normal and the idle was bouncing around too. I decided to go ahead and drive it anyway and once I started driving it seemed to drive fine. The next time I came to a stop the car idled like it did before I filled up and has been idling fine ever since.

So I have two questions:
1.) Why would the WGDC be affecting the idle when it's set above 100?
2.) What would cause the car to idle funny after filling up? I'm thinking maybe I need to check the fuel filter or one of the injectors is going bad. Thoughts?

 

I was getting a while back a miss fire and it turns out it was the MAF sensor that was bad.

 

Possibly. But the issue I had today after filling it up makes me think it's something related to the fuel system. Either pump, filter, or injectors.

 

Have you check the injector o rings? With 85k on them they are probably not in the best shape. My one FIC seal is ripped and my idle is pretty crappy as well. Just need to order a new set and take care of it.

Sounds like we have the same situation.

 

I hate to even say to try this as people have had great success with the Spoolinup COPs, but have you tried swapping in the OEM coils to see if that cures your issue? The only reason I say this is because I have had 2 different sets of used Toyota coils fail on me now...both on cylinder #2. The failure was very intermittent and was hard to track down at first... I had my second set fail on me this past weekend 2 hours from home and had to drive back on 3 cylinders! Like I said not bashing Matt's product because I was using used coils each and everytime with the kit and you never know when a used part will fail...

 

You may want to consider pulling the fuel pump assy out and look inside the tank. You might have some bad gas or water in the tank. With what you were saying about the car running worse as the tank gets lower. I've seen at my work, in fact I've got a corolla in my stall right now with the same issue. It's got water in the tank floating on top of the gas. Fairly easy to see once the pump is out and you look in with a flashlight. This may not be your issue tho it does sound somewhat like it. Good luck.

 

There is a ticking coming from my engine bay that is probably either a lifter or an injector so I'm getting real close to just swapping the injectors.

Actually, one of the reasons I bought the Spoolin Up Kit was because I thought it would fix this issue. This has been going since before I got the kit. I did try swapping the stock coils back on at the track one day but there was little to no change.

I'll see how things go the rest of the week but I'm thinking my next step is going to be to pull the pump, inspect everything, and change out the filter... hopefully next weekend.

 

Update

About a week or two ago I started smelling fuel when I would go WOT, leading me to believe I had a leaky fuel injector. I was also thinking that this might be what's causing the idle misfire so went ahead and put in some FIC 1050s this weekend that I got used from another forum memeber a while ago. When I pulled the injectors out Saturday night the plastic tip on one of them was actually broken and a piece was missing. Obviously this worried me, but at the same time I was at least happy that I thought I found my problem. Well I finally got things somewhat put back together this morning (BTW- To anyone that attempts an injector install- make sure you take off the black spacers that the fuel rail bolts run through. If they fall off, it's not fun trying to find them). Anyway, so I fired the car up this morning and the misfire and idle is now worse than before. One thing that I noticed is that it seems to run pretty smooth when the AFRs are below 13 but above that it gets progressively worse as the AFRs get leaner. I noticed the same thing before the injector swap but with the stock injectors it would idle smoothly if the AFRs were below 14. So if anyone has any input please let me know. Thanks!