Dude2005

I'm absolutely sure I got them in the right order. The wire that comes from the middle of the harness on this side goes to the cylinder 6 and the one from the end of the harness closest to the firewall goes to cylinder 4. As described here (I hope link from another forum aren't a bannable offence) I also put back old plugs and the problem is still there, so that rules out any kind of fault with new plugs too.

Hi guys, it's me again with another weird issue. TL;DR at the end. Story time first, it's a 2005 DE btw. For the past 2-3 months I had an intermittent random cylinder misfire (P0300). I did the obvious thing at first and ignored the problem. Don't get me wrong I wanted to sort it out, unplugging one coil at a time and looking for change, but by the time I was parking at home the problem would go away. It had this weird characteristic that at first it was fully random and sometimes it wouldn't even throw a code. Recently it was only manifesting itself when it was warm outside up until the engine was really warmed up, at which point it would start running properly on all 6 cylinders. One time I went home and it was still misfiring, so I've did the unplug one coil and listen for change procedure. I've confirmed that the cylinders on the left (1,3,5) work just fine. The right side was more tricky as it's buried under air intake. I've finally decided it's prime time to change spark plugs. Car has 115k miles on the clock, so about time to change plugs anyway. This week I got to it, bought a set of NGK PLFR5A-11, got my tools out and did the job. And here comes the problem. I've found, what I think was the offending cylinder. When I removed coil pack from cylinder number 6 (furthest on the right when looking at the car), it made an ungodly gurgling sound I never wanted to hear and there was a fair bit of oil. The coil pack was dripping with it and I went through 3 dozens of paper towel sheets to slowly but surely remove most of the oil from the plug well. I cleaned the coil pack and all. At that point I already changed the other 2 plugs in that bank on the right so I also changed this one. Then I went to change the plugs on the left and everything went smoothly. Some were easy to remove some required a lot of force, but no surprises. Nothing chipped, or anything like that. Everything went as planned and expected aside from the surprise oil where it was not supposed to be. When removing engine cover to get better access and following guides I've noticed that the surface of the engine block right under the mounting point of that plastic cover was absolutely pristine, indicating that it most likely was never undone since the car left the factory floor. With that in mind I don't know if these spark plugs have ever been changed. The service book has a P3 entry at the right time though. Now here comes the problem. I put everything back together triple checking to not forget any plug or bolt that I've undone. The car started smoothly as if nothing changed. It was cold and running perfectly. I didn't notice it running better, but it didn't run worse either. I went for a short ride to a store and about a mile down the road as it warmed up a little it started making a low rumbling noise when accelerating. From idle to about 2000 RPM, the noise can be heard both when stationary and just revving the engine and when accelerating in gear. The car shakes and the noise is very audible. It also comes when idle with A/C on. It causes some odd vibrations that can be felt on the steering wheel too and pressing brake pedal and revving also causes the vibrations to be felt by foot. To clarify this is not a gurgling sound, it's not misfire, the engine doesn't sound like V8, doesn't really shake, I checked the plugs to coil packs, all are in correct order, including the infamous 4 and 6 cylinder that some people swap by mistake. It only happens when it's warm; cold runs as it used to. I did put the plugs by hand at first. Hand tight, until I felt they hit the washer, to make sure I don't cross thread them, then used very short wrench to squash the washer and as I felt it was done I didn't turn any more. I though that maybe they weren't tight enough, so I did a second pass of tightening by feel on warm engine, each plug went another 1/6 of a turn on average, but that didn't help. Today I got a square drive adapter for my torque wrench and torqued all plugs to 30Nm. I know it's the max value and should be closer to 25Nm, but that wrench has a range from 30-210 Nm. Again as I did torque them to spec each one went another 1/4 of a turn before wrench clicked at 30Nm, so I thought maybe they were indeed too loose. Then I went for a ride and again at first cold engine smooth as butter, but once warmed up started making that same rumbling sound. Starting it when it's warmed up also causes it to sound very "harsh", that kind of low key scraping maybe? I don't think anything got into the cylinders, I did one plug at a time, there was no time for anything to fall in. The best way I can describe the nature of the sound and that is my leading theory right now, is that spark plug(s) are not tight enough and when I press gas it causes pressure in the cylinder to go up and some of it escapes around the plug. This could explain why the sound is the worse when accelerating and revving the engine and why it goes away at higher RPMs. It doesn't persist when I hold RPMs only when they go up. The other theory I have is that some of the oil from that cylinder 6 made it's way into the cylinder, burned and turned into a soot residue and as the engine warms up it causes premature ignition, hence the sound. My last resort would be to put old plugs back in and see if the problem is maybe with new plugs. TL;DR Changed spark plugs after having a random misfire for a while. Cylinder number 6 had a lot of oil in spark plug well. Now the car makes rumbling sound in RPM range 650-2000 when either revving or accelerating but only when warm. Sound fine when cold. Problem only manifests itself when revs go up, holding it at set RPM in that range does not result in the rumble. Picture of old plugs in attachment. I think the one that was in cylinder 6 with oil in well is the first one (from the left), but I'm not sure. They all look about the same. Worn, but otherwise fine and shouldn't cause the misfire. I blame that on oil getting between plug and coil pack. I know that oil in plug well means I need to replace valve cover as that particular gasket/o-ring is integrated in the cover. In the mean time I'm looking for wisdom. Did I miss something obvious when puting everything together. Should I put something on spark plug threads to help it seal or is it indeed oil residue in the cylinder that causes premature ignition. Should I take the car for long ride and let it burn in or should I change something and not drive it until it's fixed. Have anyone experience this before?

Yes, I did

So here goes a final update I think: It's been a while, I anticipated that it will take me around an hour to change the sensor, so I've been waiting for a good warm day ideally a Saturday, trying to avoid working on hot engine and risk burning my arms. Anyway, long story short, around 2 weeks after the initial problem started (the check engine and ESP + SLIP lights being on, car having troubles starting when it was warmed up) one day it all went back to normal. I've been driving since then (another 2 weeks) waiting for the problem to return, so if I change the sensor I could see the difference and confirm to myself that it was indeed what was causing problems. That day however didn't come. Car was starting nicely it just felt a bit handicapped and slow. Then, few days ago, I had a bad power loss for 2-3 seconds when accelerating on 4th gear, which convinced me that the problem was still there and I should change the sensor anyway. Today I finally changed the camshaft position sensor, took me 10 minutes, turns out it's a dead simple task, a 5 year old could do it. The problem I have now is the ECU being all not so happy. After changing the sensor, I connected OBD2 reader, started an app on the phone did a scan and nothing showed up. Not surprising given that the problem went away some time ago on its own and the check engine light wasn't on since then. However when I started the car (first start after sensor change), it didn't start right away. It had the same bad start it used to have, the only difference was this time it did it on cold engine. After that the check engine light came on. I had to run some errands so I took the car, previously read that the ECU may need to learn the new sensor. The ride was nice and smooth though car was a bit sluggish, must have been in limp mode. When I parked it once with already warmed up engine it had a bad start after and a few minutes after that I hit petrol station and it had bad start there as well. This time the ECU, SLIP and ESP lights all came up. I drove back home, again car giving me maybe 40% of its power. And then I tried to clear error codes for the last time. So the same app+OBD2 reader, this time showed the P0340 again, I followed the recommended steps of turning ignition, scanning codes, clearing, turning ignition off and then starting the car. It started nicely (warm engine), but the ECU light is now on. ESP and SLIP are off, and the OBD2 doesn't read any errors, but the check engine light is on. I let it run for 5 minutes, idling, reved it up to 2000RPM for a minute or so and then let is spin idle for a moment and turned it off. So my final question is, what is going on? Is it true that the ECU will learn/adjust to new sensor and it will take it some time? Why is check engine light on if there is no errors? Is that a problem with the reader/app? Should I do the pedal dance and read the code this way? Will there be any code? I hope that all I wrote here isn't too chaotic.

Thank you guys so much for all the feedback. I got the OBD2 reader today. I checked the codes and it got me P0340 (full description that I got is: Camshaft position (CMP) sensor A, bank 1 circuit malfunction). I then cleared it, went for a longer ride and the problem returned. The engine died randomly when idling in a traffic, then had a bad start and the check engine light + esp + slip is now back on. Is the error code indicative of which sensor exactly it is? I know this engine has 2 and they are not identical and the OEM supplier from what I know is Hitachi. Would it be CPS0005 or CPS0008. Or should I replace both anyway? Also on the oil situation I poured another 1 litre (for a total of 1.7L) and now the oil level is exactly halfway between min and max. Hope that running this much low on oil isn't the reason I now have a problem and just accidentally happened when the cam sensor failed.

UPDATE: So it seems that I'm a bit of an idiot myself. I've checked oil level today and it was below min. There was still oil on the dipstick, the backside was constantly getting oil all over it, but on the side with checker pattern it was dry and the oil mark was below the marked minimum. I've poured 700ml in (all I had at hand) and moved the car to a better parking spot and it started nicely as it used to - touch the key and it was on. I'm not sure if the light start was due to it being cold or because of it having more oil though. The check engine light remains on, but the VDC and SLIP is now off. I'm gonna check the error codes once the OBD2 arrives. For now the car will be parked. Thank you guys for your answers. I hope it's not gallery gasket, that one sounds expensive

Hi everyone, This is a question about engine start up issue and check engine light. It's a 2005 DE, 6 speed manual, no mods, around 109k miles on the clock. I was driving back from work today in an unusually heavy traffic that was mostly 1st gear constant stop and go. Roughly halfway through (15 minutes of driving maybe 3 miles, so warm engine) I pulled up to enter a roundabout and as I tried to start from a complete stop the car died. I didn't stall it, it felt like it died the moment I touched the gas and before I event started releasing clutch. Then the engine had a bad start. It used to start literally in one second (just touch the key and it was running), this time it felt like 2-3 times longer. Shortly before that I've noticed in the corner of my eye that RPMs have been acting weird, once or twice I've seen them jump above 1200 for no reason, while idle and then go back to 750. Then I drove past home and straight to Tesco. Parked the car, quickly got what I needed, and went back to car. Took me maybe 3 minutes. Then I had the same hard start as before on roundabout, but this time the check engine, VDC and SLIP lights, all three, turned on. I was a bit concerned about the oil pressure. Few month ago I had a nasty situation with a mechanic who needlessly replaced a sump pan and I've been keeping an eye on the oil level and pressure ever since. In last few days I've started noticing the oil pressure on idle being lower than usual and dropping to 16-18 psi when totally idle and a bit above 35 psi at 2000 rpm. When I got the car it used to hover higher, I don't exactly remember it being below 20 psi ever. I'm gonna check the oil level tomorrow morning, once it cools down. I don't have an OBD2 reader yet (going to buy one online in a moment). Does anyone have any ideas what it might be? Should I be worried? I did around 7000 miles in this car since I got it, was all super smooth, never had any engine related problems with it. P.S. apologies for long post and bad English (it's not my native).