wagomaniac Posted June 1, 2014 Share Posted June 1, 2014 So I have searched on the whole shuttering and rough idle issue but I have not found something that relates exactly to what I am experiencing. I recently bought an 05 LGT with 145k. The previous owner did the timing belt and waterpump at 140k and the spark plugs at around 138k. When I drove it home it was completely fine. Then after the first week I started noticing that when I would come to a stop, the rmps would drop to about 400-500, shutter a little, and then rise back up to normal. I also noticed that it would do the same thing when I would rev it a little while on neutral. This was happening but without the check engine light being on. However, last week the check engine light went on and it read a misfire in cylinder 4. The car was still running fine albeit the shuttering and drop of rpms when making a stop. But the check engine light went away after two days. Yesterday, I disconnected the battery to switch out the master window switch. After I was done I reconnected it and drove it into my garage. However, when I tried driving it last night, it started up fine but when I took off it stalled right when I came to stop. I kept restarting it and trying to drive it but every time it would stall as soon as I stopped pressing on the gas. This morning it started and ran but every time I come to a stop the rpms drop till almost stalling but it stays on with a rough idle. There is no check engine light on currently. Here is a video. Sorry for the seat belt chime lol http://youtu.be/UGYeodgX2M8 Any help is appreciated. Thanks Link to comment Share on other sites More sharing options...
Free Range Racing Posted June 1, 2014 Share Posted June 1, 2014 There is a ground connection point at the back of the driver's side TGV body that sometimes gets forgotten when someone takes the intake off, it can mess up the sensors and make it run poorly like that. If that checks out, make sure your hoses are all still functional. The turbo to intake hose can crack or wear through and mess up the MAF's readings, or a brittle vacuum line can really mess stuff up. Link to comment Share on other sites More sharing options...
JmP6889928 Posted June 1, 2014 Share Posted June 1, 2014 Front O2 sensor is bad. Link to comment Share on other sites More sharing options...
wagomaniac Posted June 1, 2014 Author Share Posted June 1, 2014 There is a ground connection point at the back of the driver's side TGV body that sometimes gets forgotten when someone takes the intake off, it can mess up the sensors and make it run poorly like that. If that checks out, make sure your hoses are all still functional. The turbo to intake hose can crack or wear through and mess up the MAF's readings, or a brittle vacuum line can really mess stuff up. Thanks, will look into that. Front O2 sensor is bad. Wouldn't that cause the check engine light to go on? Link to comment Share on other sites More sharing options...
nnamssorxela Posted June 1, 2014 Share Posted June 1, 2014 I am having some similar issues I've been documenting on a thread in here. I would check for a vacuum leak. This thread shows shows you how to easily and cheaply test for leaks: CLICKY After fixing the leak, I reset my ECU and I had issues similar to those that you are having on top of my normal rough idle. The car would almost stall out, then the idle would shoot up on occasion to save itself from stalling. I assumed the ECU was relearning everything after the reset, so I just drove it around for a bit and the problem mended itself. I still have a slightly rough idle, but I suspect either OCV or tuning issues. Link to comment Share on other sites More sharing options...
wagomaniac Posted June 1, 2014 Author Share Posted June 1, 2014 I am having some similar issues I've been documenting on a thread in here. I would check for a vacuum leak. This thread shows shows you how to easily and cheaply test for leaks: CLICKY After fixing the leak, I reset my ECU and I had issues similar to those that you are having on top of my normal rough idle. The car would almost stall out, then the idle would shoot up on occasion to save itself from stalling. I assumed the ECU was relearning everything after the reset, so I just drove it around for a bit and the problem mended itself. I still have a slightly rough idle, but I suspect either OCV or tuning issues. Thanks for your input! I did stupidly forget to mention that the car has a stage 1 XPT tune. Could it be a tuning issue? Now that I drove it a bit, it's not stalling anymore but it does still have the rpms dropping really low at stops. Link to comment Share on other sites More sharing options...
Free Range Racing Posted June 2, 2014 Share Posted June 2, 2014 For both of you guys looking into solving vacuum issues, I have just started selling a compete silicone hose kit I had made after replacing my own hoses fixed a ton of my running issues. Not trying to steal your thread, just seems really relevant. If you're interested, the for sale thread is HERE Link to comment Share on other sites More sharing options...
RallyMachine Posted June 2, 2014 Share Posted June 2, 2014 Seems like bad OCVs or bad injector... If you have tuning equipment like tactrix cable or AP you can monitor cylinder roughness to see if it's isolated to cylinder 4 or if youre getting some on cylinder 2 as well. If you are seeing some on just cylinder 4 I would suspect injector, plug, or coil pack...could also be vac leak as well. If you are getting roughness on 2 and 4 I would lean more towards driver side ocv. Link to comment Share on other sites More sharing options...
JmP6889928 Posted June 2, 2014 Share Posted June 2, 2014 Wouldn't that cause the check engine light to go on? Not necessarily. It sounds like your STFT is bouncing all over the place, and that's a function of the front O2 sensor. If you can find someone that has a known good one, borrow it and change it out. Only takes about 15 minutes and I think you'll find that it will solve the issue. I've had the front one go on my own LGT and never set a CEL. I know of several others that also had the same thing happen. If you do need to purchase one, go with OE. Aftermarket (I had NTK) don't seem to hold up nearly as well or run as smoothly as the OE pieces. Good luck. Link to comment Share on other sites More sharing options...
wagomaniac Posted June 2, 2014 Author Share Posted June 2, 2014 [/QOUTE]Not necessarily. It sounds like your STFT is bouncing all over the place, and that's a function of the front O2 sensor. If you can find someone that has a known good one, borrow it and change it out. Only takes about 15 minutes and I think you'll find that it will solve the issue. I've had the front one go on my own LGT and never set a CEL. I know of several others that also had the same thing happen. If you do need to purchase one, go with OE. Aftermarket (I had NTK) don't seem to hold up nearly as well or run as smoothly as the OE pieces. Good luck. Ah I see. Thanks! I'll have to try this. Link to comment Share on other sites More sharing options...
Max Capacity Posted June 2, 2014 Share Posted June 2, 2014 X2 for the front O2, it needs to be OEM if you want it to last. My aftermarket, lasted 2 years. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted June 2, 2014 Moderators Share Posted June 2, 2014 X2 for the front O2, it needs to be OEM if you want it to last. My aftermarket, lasted 2 years. Denso sensor from advance / autozone / napa is the same as OEM I believe. And you can get one for about $80. "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
Max Capacity Posted June 2, 2014 Share Posted June 2, 2014 FWIW, my wagon well rev at random times after I back into the parking spot at work. Sometimes if a move the steering wheel while parked it well have a bonucing idle for a about 3 revs. By that time I normally rev it to about 2000rpm and it comes back to a normal idle, mine is set high about 850-900rpm. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
wagomaniac Posted June 2, 2014 Author Share Posted June 2, 2014 Thanks you guys. Replacing the sensor seems like the next best step. Link to comment Share on other sites More sharing options...
gear_monkey Posted June 4, 2014 Share Posted June 4, 2014 My car has the OP's exact symptoms. Things I have tried so far are: -moved coils around..same idle but P0304 never returned. -had all coils checked at repair shop. One tested bad and replaced..idle still rough just not as bad. -spark plugs checked...look good. -smoke check done..no vacuum leaks. -I pulled both OCVs and sprayed down with wd40. Both looked mechanically sound. My next planned steps are front O2 sensor and then possibly manifold intake gaskets. Hopefully following this thread will give me more pointers. Link to comment Share on other sites More sharing options...
RallyMachine Posted June 4, 2014 Share Posted June 4, 2014 Either of you try swapping injectors? Link to comment Share on other sites More sharing options...
Max Capacity Posted June 4, 2014 Share Posted June 4, 2014 gear_monkey, thanks for meantioning the intake manifold o-rings, I was just about the say that. They normally present themselfs as a issue during cold weather. But may be now age is a facture. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
gear_monkey Posted June 5, 2014 Share Posted June 5, 2014 Well, I've never been more relieved to have the check engine light come back on..the misfire moved from P0304 to P0302 after the shop I'm taking it to moved the coil packs around. At least now I can focus on the coils, check the injectors, and clean the TB. I've been losing sleep over the possible bad piston idea. Link to comment Share on other sites More sharing options...
wagomaniac Posted August 20, 2014 Author Share Posted August 20, 2014 UPDATE: So I installed new injectors about two weeks ago. The rough idle improved but still not how it's supposed to be. However, the misfire in cylinder #4 came back on. Therefore, I installed new spark plugs a couple of days ago. The old spark plug on cylinder 4 looked very black while the others just looked old. I also swapped coil pack #4 and #2. Hoping that the code would follow if it was the coil. But the misfire still came back on cylinder #4. Anyone have any ideas on what I should do next? Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted August 20, 2014 Moderators Share Posted August 20, 2014 New plugs new injectors, swapped coil pack? Time for a compression test. "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
JmP6889928 Posted August 20, 2014 Share Posted August 20, 2014 Before you do compression test, remove the coil packs and twist the electrical contact pins slightly. As these cars age, the electrical plugs on the coil packs become slightly loose and if you twist the pins with a pair of needlenose pliers slightly, it will make everything tight again when you plug the connector back in. It doesn't take much twisting-just a little, but I have fixed a lot of cylinder misfires with this and I think that you should try it before throwing in the towel on a compression check. It just may fix the issue. Good luck. Link to comment Share on other sites More sharing options...
wagomaniac Posted August 20, 2014 Author Share Posted August 20, 2014 Before you do compression test, remove the coil packs and twist the electrical contact pins slightly. As these cars age, the electrical plugs on the coil packs become slightly loose and if you twist the pins with a pair of needlenose pliers slightly, it will make everything tight again when you plug the connector back in. It doesn't take much twisting-just a little, but I have fixed a lot of cylinder misfires with this and I think that you should try it before throwing in the towel on a compression check. It just may fix the issue. Good luck. Thanks, I'm really hoping it's not something expensive but at this point I'm pretty pessimistic. Link to comment Share on other sites More sharing options...
wagomaniac Posted August 20, 2014 Author Share Posted August 20, 2014 I also forgot to mention that it's burning a good amount of oil Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted August 20, 2014 Moderators Share Posted August 20, 2014 I also forgot to mention that it's burning a good amount of oil Uhhh, compression test. And unfortunately with all of the symptoms it really seems like you might have a ringland issue in #4. "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
wagomaniac Posted August 21, 2014 Author Share Posted August 21, 2014 Uhhh, compression test. And unfortunately with all of the symptoms it really seems like you might have a ringland issue in #4. Darn, would you happen to have a cost range for that issue? Link to comment Share on other sites More sharing options...
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