multi cylinder misfire remedy

[Q_SHIP]

Any updates?

I encourage you to use the BG product before any repairs just to see how well the stuff really works.

[renkema]

I'm in the do no harm mode. The car is running like it did before and all I've done was drive it to cycle throught the current gas in the tank. I'm suspicious that the throttle body cleaning performed by the dealer left an artifact in the flow. Like Texasoil said, it could also have been water in the gas. Who knows. But I'm convinced spending $3,500 on all new coils was a fools errand.

I got the KS and new plugs but have not installed yet. I viewed another post about a problem I'm having (and have always had since 43k miles) on startup: rich mix (know as a lean fire). That seems to indicate an issue with the EGR. I'm planning on replacing the EGR, IAC, Plugs, KS, and cleaning the plenum/throttle body. This will be a full day job. I also purchased a OBDII reader to get all the codes that may be registering. I'm relagating this all to a weekend in the garage as time is not as critical now that it's running fine. I'm also planning on step by step pics to post here.

The old physician creed: "at first, do no harm". I'm trying to follow that. I'll keep everyone informed of the progress, but in the meantime, take what your dealer service says with a Lott's wife size pillar of salt.

[QBOY]

I'm looking forward to what happens next! I too have been having intermittant problems of "missing" and have been a bit baffeld about where to start. Every time I start to look though - like you the problem goes away (lol). However I'm back which means my car is not running well again. I've repalced the plugs now, O2 Sensors - Now I'm getting a knock sensor code so that's next on my list. I'm going to try some of the things you did alsow - MAF cleaning and also the techron treatment.

Also, I've had the dealer tell me on two different occasions that an Ignition coil needed to be replaced - I had them do it for big $$ and it fixed the problem for a short period of time (3 mos). I'm not sure if they needed replacing or not but I can tell you that one of them that they replaced a year ago on Cylinder 7 - is now showing a misfire code again. I don't trust the dealers anymore - they just want you to keep giving them money to throw parts at the problem until they fix the right thing.

I wish you all of the best this weekend! Be sure to post your result!

P.S. I too haven't been able to find where the Knock Sensors are at - I'm going to oder them and I figured once I get them I might be able to match them up with something under the hood - LOL

[maxnix]

But I'm convinced spending $3,500 on all new coils was a fools errand.

Especially when they are less than $1500 form Joe.

I am a little baffled why Infiniti technicians have not identified the cause. But a dirty plenum and TB, IAC and EGR valves don't help. Cooler weather with a new coil seemed to have solved mine for now.
Modified by maxnix at 9:05 AM 11/1/2006

[Q45tech]

Like Texasoil said, it could also have been water in the gas.

The question is not if it has water but how much water.

Almost every Q fuel tank has some water in gasoline, the problem occurs when it exceeds 0.05% and settles out of suspension.

Study the specifications of the ETHANOL delivered for blending.

Water is used in the fuel transport pipelines to segregate the different batches of gasoline why Ethanol cannot be transported by these pipelines, so gasoline has some water all the time.

[Q_SHIP]

Make sure you replace the ks harness with the ks's.

[renkema]

look at this link for the KS location

http://www.q45.org/plenum.html

[renkema]

to be clear, the $3,500 was for all new coils, new KS and harness fully installed (which equalled about $1,500 labor, $2,000 parts)

If that would have been a definitive fix I wouldn't have an issue with the cost. All they could say was "that should get it"(read no guarantee). That's not good enough. Could they diagnose it, probably, if the right person was on it. But that's the same problem we all have with everything, getting qualified help. This is not broad brushing dealers, just mine (and maybe just the service tech on mine). I have not considered a straight Nissan dealer as I assume they would know less that the infiniti dealers.

I'm going to address the KS, EGR, TB, plenum, an IAC as you and others suggest.

I'm still surfing the posts here to further diagnose the problem of sluggishness uphill. I think I'm getting a lean or rich situation which is not happening near WOT and think that is the primary cause of my ills with the cylinders/missing.

[maxnix]

to be clear, the $3,500 was for all new coils, new KS and harness fully installed (which equalled about $1,500 labor, $2,000 parts)

I have not considered a straight Nissan dealer as I assume they would know less that the infiniti dealers.

With a FSM, torque wrench and a set of sockets and parts from Joe, you can do it yourself. Better and for a lot less (lots of labor to clean plenum and EGR and IAC valves.)

Almost no Nissan techs have ever worked or been trained on a VH series V8. They may be great on VG and VQ and even the new VK, but even the best ones are lost on the VH. Most won't admit it, either.

[renkema]

[QUOTE=maxnix]With a FSM, torque wrench and a set of sockets and parts from Joe, you can do it yourself.

I've got lots of tools but no FSM. Where can I buy one? Scottsdale's where I've been getting my parts. Would they have what you suggest?

[maxnix]

I've got lots of tools but no FSM. Where can I buy one?

The best place is http://www.nissan-techinfo.com/infiniti/ as they have the TSB also, and some other publications all in Acrobat format. One day subscription is $20, a bargain for the knowledge. Site is not intuitive to navigate. 1994 and later, only.

http://www.phatg20.net has many of the FSM.

[renkema]

[QUOTE=maxnix]Cooler weather with a new coil seemed to have solved mine for now.

Cooler weather?? That's interesting. The temp here dropped about 20 degress and the car seems to be more responsive at the lower end of throttle application. Cooler air is heavier. Does that mean it has more Oxygen. If so, I must be running too rich in hotter weather. If these assumptions are true, what part or parts is supposed to change the mix according to these changing conditions? The O2 sensors??

[Q45tech]

I finally got to look at the last 3 months of "shop magazines" they all contained numerous articles on how to diagnose "random misfires" in domestic and import vehicles. Every model seems to have some prolems.

Could it be the US Fuel composition?

Seems to be the most common problem [considering the number of articles].

Ethanol, dirty injectors, carbonized pistons, valves, and fouled spark plugs.

Failed coils [rare] and the spark plug extension [oil coated]/cracked].

Food for thought: From a good BMW FORUM:"I own a 1998 540i (E39)just had it back from the dealer who replaced the cam sensor and O2 sensor, $640.00 and one week later I have another problem. In an effort not to have to go back to the dealer I purchases a FCXII scan tool which says that I have random misfiring in the engine. It also specifically designated cylinders six and seven with random misfires. I checked under the covers and noticed that my inner valve cover gaskets have leaked some oil on top of numbers six seven and eight spark plugs. Thinking this was the problem I cleaned up the excess oil, replaced the spark plugs and checked 0hms on the coils. This did not correct the problem. Any ideas will be appreciated. ""..........................

"AnswerPhilip, Leaking valve covers can indeed cause misfires, I would replace them post haste. Mark the coil and swap them to different cylinders. Note the new locations and clear faults. Drive the car and see if the faults return to same location. Also check the PCV valve on the back plate of the intake manifold. With the engine idleing, turn the oil filler cap and crack it open just a little bit. If you have a huge amount of vacuum under the cap or if it makes a strange honking noise the Valve has failed. Also look for vacuum leaks around those cylinders by spraying brake cleaner down on the intake gaskets and around any manifold or throttle seals and listen for a change in RPM. That should give a few avenues to try"

[maxnix]

Good post, but the only seeping valve cover I have is on the other bank.

No oil around any plugs or coilpacks. Tunnels are spotless.

[Q45tech]

Just as a test I Googled xxxxxx radom misfire xxxxxx= every car brand Audi thru Volkswagon and found at least 600 citations for each brand.

Toyota had 11,000+Ford 26,000GM 17,000Lexus 1160Infiniti 952BMW 823Audi 586

[renkema]

This post brings me updating on my "stumble"/"multi-cylinder misfire" issue. To the point, my problem has been solved.

To summarize my problem, I had the same "stumble" that has prompted many posts and caused quite a bit of discussion. To be specific, my car was registering K/S codes on a regular basis with the multicyl misfire code on a sporadic basis. The physical evidence came and went but by the fall of '07 (after a year of on/off occurences) it was repeatedly pronouncing itself by 1) engine stumble while accelerating uphill or downshifting and 2) a shudder (like a small backfire) while at idle. This manifestation at idle pointed away from the transmission and toward the combustion chain.

All the posts on this same issue point to the coil packs. So, I purchased a full new set of OEM plugs, the KS and harness from Joe and got a full set of Hitachi coils from an importer in Connecticut (time will tell if the Hitachis are really OEM, but the price ($550 for 8) was worth the gamble at this point). I would have done the install myself but my valve cover gaskets were leaking and I had strut work that needed to be done.

I had my new good friends in Atlanta (Ty and Dennis) take it from there. Result: issue and codes are completely gone!!!!! They simply replaced the parts (and gave me the old ones as soveniers) and the car runs like the day I bought it. Do I know if it was the KS? No. Were we able to determine which coil was a possible offender? No. Could we? maybe (would it be just one, could it be more than one, you get the picture) Am I satisfied with the result? You bet.

So I'm back to enjoying my car while at the same time thwarting my wife's attempts to "upgrade".

Thanks to all who have opined on this issue. The insight and direction have been immensely helpful.

[Q451990]

Thanks so much for updating us on this! The misfire issue appears to be the weak link on the Y33. I think several members would be interested in getting contact information or a link to the Hitachi coils from your importer. I think as T3's business shifts more and more to the Y33 (at least for their Infiniti side of the business) they will figure this thing out for good... if anyone can, they will.

Heath

[bullittandy]

X2 on the update, that makes a ton of difference for developing a theory about what's happening with these cars.

I've got a 99 with the idle stumble, I haven't driven it too much yet (no tag) but when I'm driving it daily I plan on performing an experiment by replacing the K/S, then the coil (s) and then cleaning the EGR, upper intake and we'll see........

[AlabamaDan]

Oooh oooh let me:

You can download the FSM for free:

http://www.nicoclub.com/FSM/Q45/

Set aside an afternoon a couple reams of paper and a hole punch.

[renkema]

First, a disclaimer. The coils I bought are listed as Hitachi by the seller. I have no way of confirming this fact (they may be Mattel for all I know). The real test as to whether these are suitable will be sometime next year (when either they are still functioning properly or I have the return of the issue).

The importer (FCP Groton) lists each coil for retail/our price of $231.98/$134.25 or $1,074 for 8 on their website. I got them for half of that (approx $550) for buying 8 via their add on ebay (not via their website).

My thought on the risk/rewards were as follows. If I replace the KS, coils, and plugs and my problem goes away, I know it was one of those issues. Given the prior input here on NICO (and from T3), the coils were the likely (but not necessarily the definite) candidate. If they were the definite problem, I could maybe fork over the $1,800, but if they weren't, I'd have made a large investment for no reason. Hence, I decided to take the risk on the lower priced items. Cheaper price usually means cheaper product, but in the age of overstock, production run excess, I decided to take the chance. If the problem is fixed and they work forever (defined as get me from 100k to 200k); then Home Run. If they work for a while and the issue returns, at least I know that the issue is the coils. Then I can decide (depending on how long they lasted) to repeat the cheap approach or go full tilt OEM.

If others have purchased these "Hitachi" coils from this or another supplier and are Happy/Sad, please share your experience with the group.

Thanks again to T3 and everyone else who have commented/assisted on this issue. I will be sure to give periodic updates on this year's performance stability/degradation.