'97 Q45, stumbling idle through 2000 rpm m.o.l.

[maxnix]

Really depends if he has a top of the line OBD II code reader like a SnapOn unit.

The Autozone ones won't cut it.

[paranoidjack]

did a diff synthetic flush and a transmission flush today. This might attack the transmission question.

I haven't found it since my last tank of gas (which, unfortunately I got 100 mi away). going on 3 daze now.

[maxnix]

I haven't found it since my last tank of gas (which, unfortunately I got 100 mi away). going on 3 daze now.

"It" being the stumble?

Mine's gone, so far. Runs and idles great, like new. We'll see how long that lasts.

[paranoidjack]

"It" being the stumble?

Mine's gone, so far. Runs and idles great, like new. We'll see how long that lasts.

ya, the stumble. If this doesn't work I'll start cleaning out intake parts, that's the next step. We should all use one of the trip resets between stumbling. I drive alot of miles, 6k in 8 weeks already, so that's how I'm going to measure it.

[maxnix]

Oh, when it was occuring, it became more frequent as time passed. When it got to doing it in cruise, it all had to be cleaned. Manifold and lower runners were fun, not!!! Need a worn out Dremel steel brush to get the EGR tube clean. A new brush works well on the TB, EGR, and IAC and the parts of the intake one can reach.

Must have all the required gaskets on hand.

Upper to lower manifold.

2 EGR

TB

IAC

[xmateo]

Just bought a 99' Q45t a week ago. It has 90,000 miles on it. I have noticed its doing the same thing. I will be watching to see if anyone comes up with anything. I got a 3yr/36,000 bumper to bumper with it. I'm going to collect al the little issues for about a month and bring it in to have them fixed. Its a $100/ each drop off at the dealer. It doesn't matter if I have 1 or 10 issues.Chris

My '99 Q45 with 81k miles was doing this as well. Believe it or not, I started using premium grade (high octane) fuel and now the problem is gone. The car has much better and smoother acceleration. I am getting much better mileage now too - enough to more than justify the higher cost. Try it and report! I couldn't believe the difference.

xmateo

[miata007]

I've been doing that for a while already and did see some improvement. I am going to have get some BK44 one of these days. For some reasons, when the gas tank is 1/4 full or less, the problem is more visible. Could it be a bad fuel filter or a dirty fuel tank?

007

[maxnix]

For some reasons, when the gas tank is 1/4 full or less, the problem is more visible. Could it be a bad fuel filter or a dirty fuel tank?

Knowledgeable members never let their tank go below ¼ full!

Have you tried ISO-HEET yet? BG44K in the last tank before every oil change? If these don't cure the symptoms, then look into tank contamination.

Fuel, oil and cabin filter change every 12K miles.

[xmateo]

Fuel, oil and cabin filter change every 12K miles.

Does the 99 Q have a cabin filter? If so, how does one go about replacing it. I am not familiar with the location of the filter, etc..

[maxnix]

Does the 99 Q have a cabin filter? If so, how does one go about replacing it. I am not familiar with the location of the filter, etc..

Yes.

Please check the manual or search. There are at least 3 threads on it.

[sdkhalsa]

It seems to me that what has been overlooked in the various diagnostic efforts is failing to try to localize the miss to a particular cylinder before going after systemic problem. This could be most efficiently done with a consult diagnosis, or better yet, using your own diagnostic rig in which you could test it over a prolonged period of time. Sounds like it could be an intermittant problem with particular injector(s), coil(s), or harnesses.

[paranoidjack]

still good, no stumbling for about 500 mi now (2.6 tanks)

[paranoidjack]

how is everyone else doing with this? Mine is back in a big way, seems that when there is rain/humidity it gets much worse. Does anyone else find this? I just ordered my o2 sensor from joe, maybe that will help....from the sound of it, probably not because no one else has mentioned a CEL/o2 sensor.

We shall see...

[bullittandy]

I had this stumble on my 97 a couple of months ago. Only at idle, only a couple of times and I only noticed it at one stop light on my way to work. This stoplight is on a slight hill. I thought it felt exactly like a carbed car's normal idle fluctuation. Sounds like people are narrowing it down to a fuel issue but here's the work that I've done to my car and the idle shake doesn't exist anymore (however it was never consistent and I cannot point to one cause)-new fuel/air/oil and cabin filter (I doubt its the cabin filter though )-new K/S and harness-4 new O2 sensors-fuel injection cleaner (numerous brands including BG44K)-wiggled MAF sensor harness-TB cleaning-new PVC's

I think it may be a shiver just like people get and cannot be explained.

[miata007]

Thanks for posting! By the way, nice job on the wheels.

007

[maxnix]

It seems to me that what has been overlooked in the various diagnostic efforts is failing to try to localize the miss to a particular cylinder before going after systemic problem. This could be most efficiently done with a consult diagnosis, or better yet,

Yeah, it's crept back into my wife's.

Consult or OBD II next to check for cylinder malfunction.

Need to post my pictures of the manifold from the bottom. EGR gases definitely are more severe on cylinder 3 & 5. I will post the pictures in IOM in a couple of weeks when I return to Austin.

[texasoil]

Lots of locations now have significant (up to 20%) ethanol in premiun fuel. It can quickly pick up any corrosion product from trace water and trace water and move it into the fuel injector body.

You should check the coil resistance of all the fuel injectors to ensure they are good (12-14 ohms) since even trace ethanol will ruin the coil insulation.

If I remember correctly, the factor (dealer) service procedure with a coil misfire (should set a CEL code right away) calls for replacing all 8 ignition coils $$$$.Why? maybe they think the others are likely to fail shortly. Unfortunately, running with a failed coil will often ruin the catalytic muffler and soon lead to another CEL indicating that failure.

[kimsracer]

First , Thank you to everyone who offered help and advice regarding this problem.

To make a very long story short....

Since I had noticed a positive difference after using various cleaning agents through the brake booster vacuum line but with none of the cleaning agents giving better than very temporary results, I decided to use something that I am sure will raise some eyebrows.I pretty much checked all of the obvious and obscure mechanical and electrical components on the way to this solution, so if this saves you from having to shell out any more money and time why not try it?I have been using a household cleaner named Greased Lightning for everything from removing dirt, bugs and sap to oil and grease for a while and decided two nights ago to try it through the brake booster vacuum line out of desperation. You can get this stuff just about anywhere except church; from the dollar general to Wal-Mart. I first ran a can of Berrymans B-12 through and let it set for 5 or 10 minutes then ran half a bottle of commercial strength Greased Lightning through the same line and let it set another 10 or 15 minutes. (Half a bottle of Greased Lightning that comes in the spray bottle)I then started her up let it cough out the mixture and went out for a drive.

FOR THE FIRST TIME SINCE THE DAY AFTER I BOUGHT THE CAR, IT RUNS LIKE A Q SHOULD. NO STUMBLE, NO HESITATION, NO PROBLEMS!!!!!
Modified by kimsracer at 9:26 PM 7/10/2006

[maxnix]

Yeah, it's crept back into my wife's.

Replaced failed #2 coilpack with new one from Joe. Problem cured.

I determined it was the coilpack when I swithed it to #4 and the subsequent OBDII scan fault code indicated #4 had a misfire.

Again, I will post pictures of both.

[anggarci]

First , Thank you to everyone who offered help and advice regarding this problem.

To make a very long story short....

Since I had noticed a positive difference after using various cleaning agents through the brake booster vacuum line but with none of the cleaning agents giving better than very temporary results, I decided to use something that I am sure will raise some eyebrows.I pretty much checked all of the obvious and obscure mechanical and electrical components on the way to this solution, so if this saves you from having to shell out any more money and time why not try it?I have been using a household cleaner named Greased Lightning for everything from removing dirt, bugs and sap to oil and grease for a while and decided two nights ago to try it through the brake booster vacuum line out of desperation. You can get this stuff just about anywhere except church; from the dollar general to Wal-Mart. I first ran a can of Berrymans B-12 through and let it set for 5 or 10 minutes then ran half a bottle of commercial strength Greased Lightning through the same line and let it set another 10 or 15 minutes. (Half a bottle of Greased Lightning that comes in the spray bottle)I then started her up let it cough out the mixture and went out for a drive.

FOR THE FIRST TIME SINCE THE DAY AFTER I BOUGHT THE CAR, IT RUNS LIKE A Q SHOULD. NO STUMBLE, NO HESITATION, NO PROBLEMS!!!!!
Modified by kimsracer at 9:26 PM 7/10/2006

I have this same problem on my 1998 Q45. Can you post any pictures for running this grease lightning through the vacuum line? thanks

[bullittandy]

Replace the coils.

[goody90q45]

Replace the coils.

Andy is always right and speaks from experience. Forget the Greased Lightning as the fix will only be temporary.

Replace the coils.

[anggarci]

All 8 coil packs, looking at them online they run up to $800 for all of them! I had the pulgs changed and also an injector flush, now getting codes: P0325 Knock sensor, P0330 Knock sensor and P0301 1 cylinder misfire. Is there no way of telling which coil it could be? Another Nissan mechanic told me to have all the injectors changed. I guess I'm leary that if I have to change all 8 coils and it doesn't fix it then I would have to change all 8 injectors that is about $2000! Any shopping tips if this is the case? Thanks...

[Infinitiguy19]

.

[goody90q45]

All 8 coil packs, looking at them online they run up to $800 for all of them! I had the pulgs changed and also an injector flush, now getting codes: P0325 Knock sensor, P0330 Knock sensor and P0301 1 cylinder misfire. Is there no way of telling which coil it could be?.....

P0301 code is Cylinder 1 misfire (not 1 cylinder misfire) so it looks like you may have already found the dead coil. You can confirm this by swapping the #1 coil with the #5 coil and see if the code follows to that cylinder. I say #5 because on the G50 #1 and #5 are a different configuration than the other 6 coils. This may or may not be the case for the newer Q's.

The reason your being told to take the plunge and replace all 8 coils is that your engine is at the age and mileage where you could be doing this 8 different times over the next few years and possibly paying a mechanic 8 separate times to remove all the engine shrouds to get to this month's bad coil. Consider yourself lucky this time that the ECU told you which cylinder is bad. Most of the time you get only the generic misfire code and you're left guessing which cylinder it is.

There's nothing wrong with your injectors or knock sensors (secondary code due to the misfire). Leave them alone.

Once you get through the coil issues your car is pretty bulletproof. Good luck.

[bullittandy]

All 8 coil packs, looking at them online they run up to $800 for all of them! I had the pulgs changed and also an injector flush, now getting codes: P0325 Knock sensor, P0330 Knock sensor and P0301 1 cylinder misfire. Is there no way of telling which coil it could be?.....

P0301 code is Cylinder 1 misfire (not 1 cylinder misfire) so it looks like you may have already found the dead coil. You can confirm this by swapping the #1 coil with the #5 coil and see if the code follows to that cylinder. I say #5 because on the G50 #1 and #5 are a different configuration than the other 6 coils. This may or may not be the case for the newer Q's.

The reason your being told to take the plunge and replace all 8 coils is that your engine is at the age and mileage where you could be doing this 8 different times over the next few years and possibly paying a mechanic 8 separate times to remove all the engine shrouds to get to this month's bad coil. Consider yourself lucky this time that the ECU told you which cylinder is bad. Most of the time you get only the generic misfire code and you're left guessing which cylinder it is.

There's nothing wrong with your injectors or knock sensors (secondary code due to the misfire). Leave them alone.

Once you get through the coil issues your car is pretty bulletproof. Good luck.

What he said, cause he is also always right.

[anggarci]

ok, will work on this, on weekend and let you all know. thanks so much!

[anggarci]

So is the Hitachi ignition coil the OEM part for infiniti? When I go to infiniti based websites it does not say then I go to general auto parts websites and it says Hitachi. What brand do I buy and from where???
Thanks!!!

[Q451990]

I would buy OEM from www.infinitipartsusa.com - I seem to recall the pricing being pretty much the same as the non dealer sites for the Hitachi branded parts?

Heath

[elwesso]

Or you could take a risk and buy a few used one from another Q...