plat

I think my car has always done this but it is definitely worse now for some reason. I made a thread about this because it seems different from the common rough idle people have sometimes.

When the car is idling, it is usually smooth except for random kicking where it seems like the ignition just cuts out for a split second and the engine jerks enough to physically feel and sometimes it's strong enough to see the tac flinch down slightly.

These events could be seconds or minutes apart. Completely random.

They are much stronger when the a/c is on and idle is higher. But if I hold the engine just above idle, like at 1,000 rpm, this does not happen. Otherwise the car starts, runs, and drives fine. There are no codes except the rear O2 sensor.

in reading about this it seems like the IACV or MAF or throttle body/sensor are the most common problems with idle issues. But I don't see how those could cause such a momentary issue as I have?

Idle speed is the same as it has always been, like about 850 with a/c on and 550 with a/c off.

I am leaving tomorrow for a 400 mile road trip tomorrow. Do you think this could get worse or give me problems soon?

Zerodrag

iTrader: (1)

Are you sure that isn't just from the quick voltage drop when the radiator fans kick in?

plat

Yes, no relation to the fans switch on/off. But it does feel similar to that, when an electrical load comes on and the engine bogs momentarilaly.

However, this is much more a sharp and sudden bump than electrical things doing that.

It usually happens so fast that you can't see any change in rpms.

JvG

Probably related to the air conditioning. Has it been refilled recently?

Do you hear the ac clutch do its thing at the same instant you notice the idle fluctuations .

plat

No actually, I've never done anything to the a/c. I don't hear any click like the a/c clutch or anything else unusual when it happens.

It can be very rapid sometimes, like several times within a few seconds.



I know it's really hard to see and hear but it does it probably a dozen times or more in this video. Engine kicks around some at about 0:12 - 0:15 and you can see the tach is unsteady when I first get in the car and then it drops noticeably at 1:04.


Because it is fast and unpredictable, my first thought is that this is an electrical problem that is preventing ignition somehow.

max ride 41

iTrader: (4)

personally, i think your crazy. i wish my max ran that smoothly. the needle jumps a tad, that's normal imo. did you scan for codes?

plat

I almost wish I was but this is a change for my car. It doesn't look like much but you can feel it in your seat when it kicks, that's the best way to describe it. Very sudden and sharp bump but too fast to see from the outside.

I should normally not be able to tell if the engine is running by feel or sound when I'm inside with the windows up, more or less.

I guess the closest thing is when it's idling rough for some reason and you get a lot of vibration from the engine, but it's just one strong pulse of that vibration at a time.


Yes, no codes except the rear O2 that's always there. I actually had it scanned with a real tool this time too.

Turbobink

iTrader: (2)

I saw and heard absolutely nothing out of the ordinary in that video.

max ride 41

iTrader: (4)

i agree, you might feel a little jump, but trust me, with no codes you'll have to wait till you get one or it gets worse.

Zerodrag

iTrader: (1)

All I saw was the idle dip a little at the 1:05 mark, but that could be fans kicking in. Maybe there are issues with motor or trans mounts if the vibrations are that bad?

JvG

I don't see anything unusual.

it's normal for engone speed to fluctuate slightly when the fans or especially actually turn on or off.

max ride 41

iTrader: (4)

fixed

plat

Violator

You're the one with coils going bad right? I believe ignition circuit is a code for coils. Don't quote me on that but I know a bad coil can also cause a rough idle and stumbling acceleration. Somewhere your air fuel and spark mix is bad I'm guessing it's still part of the whole issue with your coils unless you just haven't cleared your codes

plat

I did clear the codes and the stumbling and ignition circuit code just popped up after driving 200 miles on my trip.

After driving 3 hours, took off from one light, fine. Next light it just went to crap for no reason.


I am but this seems different. When coils have failed, I got a misfire on cylinder #X all but one time(other time no code at all). And one time I got both misfire and ignition circuit codes at the same time. But never just ignition circuit.

Also, unplugging each coil at idle has shown that all are firing normally then and there is no evidence to point to one coil in particular as being bad.


Here's what I can try. Since I have a good spare coil for each bank, I can swap out each coil individually, drive, and see if the problem(s) go away.

On another note, could the condenser have anything to do with these issues? Someone on another site suggested just unplugging it and see if it gets better. What do you think of this?


For the idle kicking, this is definitely not normal. I've driven this car every day for 15 months and this is obviously different and bad behaviour. I know how the engine bogs down a little when the fans come on or when you hold the power window button down and this nothing like that. The fans are running continuously in the video, as well as all summer because I keep the a/c on. This is definitely a ignition and/or electrical problem and I would be very surprised if it wasn't related to all the other issues I'm constantly having with the ignition.

plat

Guys I have a serious problem.

I tried replacing the 1, 3, and 5 coils with the new ones to eleminate them as an issue and the #1 came out like this. That bottom part is missing because no coils will actually fit into the hole with that part on there. I cannot install a coil on #1 without removing that rubber which I'm sure is important insulation. Could that missing part be causing my issues?


What the hell do I do now since I cannot install a complete coil in that cylinder? I see no reason why it doesn't fit, the hole and spark plug look the same as the others.

Zerodrag

iTrader: (1)

If the fitting is still in the galley, maybe you can use a set of needle-nose pliers to get it out? Other than that, wouldn't you just be able to install the new coil in there without the fitting on it? This is assuming the fitting is still around the plug and not offset.

plat

Yes, actually it is. Hard to see at first. Do you think if I pulled that part off the new coil and just plugged it in down in the hole, it would be ok? In case I can't get the old one out

plat

I did get that part out with some difficulty luckily.


I just took the 4 remaining original coils out - #1, 3, 5, and 6, and put in new ones in those places. Both problems totally gone, idle kicking and stumbling, and no ignition codes back on after test driving.

So I tried to figure out which of those four was the problem by putting each one back in one at a time, and see if the problem returned. The symptoms did not come back with any one of those four reinstalled.

Then I put all four originals back in their original location and the exact problems came back, kicking and stumbling. So apparently no single coil is bad, but only when two or more of those four are installed together, I have a problem. Please tell me how this is possible. How can I have six good coils but they **** up when run together?



Is it possible that a particular coil isn't working well with a particular sparkplug? Because when I put them back in one at a time, I put them all in #1 because that is the easiest to access. So maybe the plug and coil pair for #3 or #5 is the problem and my test didn't catch that because I moved them?


Edit: Indeed, the coil from #5 alone causes the problems. When I put a new coil in place of the old on #5, there are no problems. But also if I move the old #5 coil to #1, there are also no problems. So that coil is only a problem on that particular cylinder. Next I will pull all the plugs and see if there is some disparity between #5 and the rest or something.

JvG

You might be on to something.

How long have those plugs been in the engine.

I'm just going to guess here. I understand that a badly worn plug makes the coil work harder than normal. This might cause it to get weak.

So if you attach a good coil to a bad plug, the plug will fire almost normally. .... for a while. And if you move the weak coil to a good plug, it would also fire almost normally. But a weak coil on a bad plug would cause misfire.

a test would be to move the problem coil and it's plug to the cyl next to it. I'd expect that the problem will move along with it.

Or you could compare what the electrode of the problem plug with a known good one.
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I would replace the spark plugs unless they have been replaced lately.

Good detective work.

plat

I'm not sure about their age, they came with the car. I pulled the evens recently and they looked great but was too lazy to pull the odds. Maybe somebody in the past was too lazy to change them too.

JvG

Ding, Ding Ding, Bingo.

Change them . It's easier than it looks. They must have a lot of miles on them.

As I recall, you need to unbolt some things back there to get access.

It's a good ideal to attach a swivel joint on the ratchet wrench. Some long extentions are required.

plat

How do you think they look? Top three are 1, 3, and 5 from left to right. Bottom three are 2 4 6 left to right. Gaps are about 0.042 give or take and pretty close. I can see some rust or something around the porcelain of #5, wonder if that would have any effect?






I just drove with the new ones and new coil for #5. No apparent issues but not an improvement over how it has always ran, I would say.

Zerodrag

iTrader: (1)

I would say just replace the plugs since they are/were out and run with the new coils. Keep the old ones as spares (labeling each of them to identify which cylinders they were from) and call it a day. Wait until this problem comes up again later and use the original spares to troubleshoot.

max ride 41

iTrader: (4)

here's a question that will blow your mind, i have an 07 sonata with 79,500 on it and the plugs are original. gas mileage sucks as i'm getting 14 to 16 miles to the gallon, dealer says they're good till 100,000, i think he's smoking something. 11 y/o plugs, not an easy job to replace on this car either, 2 hours to rip apart back half of motor. car seems to run really good other than the gas mileage. it is a 3.3 6 cylinder and i drive the crap out of this car as maxy is out of commission pending some repairs.

JvG

the platinum or more likely iridium plugs can last 100 miles or more. Unless the car burns oil I suppose. Id say your problem is elsewhere.

I've mentioned that BAFX scanner. One of its function's monitors if the ecu is addiing or subtracting fuel compared to what the indended mixture would be. It would probably indictate that additional fuel is being added.

one possibility would be a bad oxy sensor. The scanner also indicate's the voltage it puts our vs ideal.

One more possibly. A friend of mine has on 07 corrolla. Has 60 k on it. He is in his late 70s.
I did not have that scanner yet. So I replaced the iridium plugs. Which were supposed to last till 120k. They looked crusty. Didn't know why at the time. I replaced them with platinum. He won't be driving long enough to need to replace those. There was no change in mileage. No codes. Darn.

Next piece of guesswork., let's replace the oxy sensor. Which was fused onto the exhaust manifold. Located right next to the fire wall. So I removed that. Wen to a lot of work breaking off the oxy sensor, the stub was still fused in. Did some work with a saw, a cold chisle, and had to to retap the hole. Curses.... reinstalled the manifold and new sensor. No codes. Still no change on mileage.

So bought that scanner . Which said that it was burning rich as flock. Also showed lower than normal engine vaccuum. The scanner said that it was adding lots of fuel. Which would explain the crusty plug.

I did some research. Those are known for having a bad intake manifold gasket which causes an air leak, low mileage, and no codes. Hmm
I bought that gasket for about ten bucks.

The scanner said that no extra fuel was being added. My friend's mileage increased to normal.
We got 46 mpg on a long day drive.

So I'm thinking that you might have a vaccuum leak. I had low mileage and low performance on a car with a carburetor. Low vacuum too. I had replaced the carb recently. I had not tightened the mountil bolts enough. They had worked loose. I tightened them. All good after that.

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98maxBK

I know exactly what you are talking about. My 98 SE has been bucking like that only when stopped while in drive/ reverse with foot on brake. Idles fine in park/ neutral. Checked all the same things you did with no luck. No codes either. Started doing it all of a sudden last week.
Mechanic thinks I possibly got some bad gas. Threw a bottle of dry-gas in the tank, seems to be getting a bit better. Only does it rarely last few days. Originally it was every time I stopped.