y33 idle jerk / hesitation discussion (lets fix this!!)

[maxnix]

1.) I don't think OBD-II scanners can find a misfire without a CEL-am I wrong?

2.) Let's be realistic, cleaning the intake is a waste of time.

1.) Yes. You just wont' know it without a scan.

2.) Spoken by someone who I know has never done unless it was on a moonless night at midnight. If you had, you would know the EGR tube in your car's plenum is sealed shut by now.

[bullittandy]

1.) Yes. You just wont' know it without a scan.

2.) Spoken by someone who I know has never done unless it was on a moonless night at midnight. If you had, you would know the EGR tube in your car's plenum is sealed shut by now.

1. This doesn't make any sense. If the ECM doesn't catch the cylinder misfire (and trigger a CEL), then how is a hand-held OBD-II scanner going to catch it?

2.I didn't say EGR did I? No, I said intake. They are different parts. If I had wanted to say that cleaning the EGR system was a waste of time, then I would said, "Cleaning the EGR system is a waste of time."

Cleaning the intake is a waste of time (for curing a cylinder misfire), how do I know? Because your one of the few/only who have done it and what did it do for you?- Nothing. How do I know, because you're misfire reapeared after three weeks-remember? Telling people to yank off their intakes to clean them is bad advice (if trying to cure a idle misfire) considering the amount of labor involved, especially for someone paying someone else to do it. It is okay advice for someone who wants their car's intake to look the same inside and out.

You know what would have been really good advice? If you had been courteous enough to say in your first post, on the first page that you cured your misfire by replacing a bad coil. Instead you (Maxnix) said "It's not as you will see if you read the previous thread on this subject. Well discussed in that thread also, even by people looking for a magic bullet, which dosen't exist."

Except that people wouldn't have found the solution because you didn't post your solution (bad coil) in that two year old thread!! Of cousre its there now, after someone chided you about it.

Cheers!

[Q45tech]

OBD2 has a threshold before codes are set and MIL comes on.The Consult II and III have single hit capture modes [or you can set it 1.5. or 10 sequential faults reports].

I usually just monitor a sensor [let it data store a stream of data and look at every O2 sensor swithch point.

At 600 rpm that 10 revs per second or [4 x10] 40 cylinders firing per second.

So every 25 milliseconds you expect a O2 switch............to simplfy things you only watch 1 - O2 bank at a time so you have a blank time as the other bank of cylinders alternate then after you've given one bank a clean bill of health you monitor the other O2....................eventually you catch the misfire.

Even if you have to spend an hour watching 100,000 cylinder fires.

The Consult always stores 3 seconds [600 snap shots of all data] of previous history so if the trigger sets you can go back 3 seconds in 5 millisecond intervals [PRIOR TO THE EVENT] and see what caused the trigger to set and alarm.

Obviously cheap code readers don't have these features found on $6,000 devices.

If you can feel the misfire it can be diagnosed by an expert technican* or engineer with the correct test equipment.

* Whether or not a particular dealership [or regional engineer] has an expert technican is always open to debate. I know a few in US.

[maxnix]

1. This doesn't make any sense. If the ECM doesn't catch the cylinder misfire (and trigger a CEL), then how is a hand-held OBD-II scanner going to catch it?

2.I didn't say EGR did I? No, I said intake. They are different parts.Cheers!

1.) Wrong again. At least you are consitent!

2.) Since you have never removed your plenum, you obviously don't know about the EGR tube inside the plenum.

Every village has its mentally challenged person and this board has you.

[bullittandy]

1.) Wrong again. At least you are consitent!

2.) Since you have never removed your plenum, you obviously don't know about the EGR tube inside the plenum.

Every village has its mentally challenged person and this board has you.

You know, I'm really trying to help people here, why don't you participate?

1.Yes, a $6000 machine will catch the misfire, just as Tech said, how many people have one? Not many, and certainly nobody on this board and nobody that is trying to solve this problem. Will a hand-held OBD-II scanner find a misfire that HAS NOT triggered a Check Engine Light? No.

2. Cleaning the intake/plenum is not cleaning the EGR system. Regardless of how they are connected.

And even though I haven't pulled my plenum off, I did know that the EGR system is attached to the intake. How?

Announcement for everyone reading this thread!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Maxnix solved his misfire by replacing a bad coil, not sure which one, or how he discovered which coil was bad-he won't say. It would be very helpful if he would.

He did not solve it by removing his plenum, cleaning his plenum, cleaning his EGR, or by cleaning his ears.

[texasoil]

Now now gentlemen, this subject, while so frustrating to solve, is not worth generating animosity. MANY things can cause an intermittent, occasional mis-fire. A sticky injector can also have a bad spray pattern, and with dirty intake valves, the too small amount of fuel just won't catch fire right at idle--and this 'weak cylinder' disappears (masked) at higher speeds. Ignition coil failure is seldom 'intermittent' in that once it happens, it usually doesn't get better. However, with a weak spark, a borderline too lean mixture may not catch fire (ignite), so fixing the too lean condition (from a vacuum line leak, weak injector, low fuel pressure, etc., MAY temporarily 'cure' the intermittent mis-fire--but not fix the other culprit--which WILL get worse.

[maxnix]

Thank you for reiterating what I have previously said about three times in this thread. Possible causes (of which there are many possibilities and combinations for similar symptoms) have to be eliminated systematically in a controlled manner.

No way to over come poor reading comprehension, I guess.

[Mopar]

UPDATE!!!

Guys as all of you reading this, I had the jerking/hesitation problems too. I just changed the spark plugs (NGK) and the coils(from a 2000 Q) and my car is back alive!!!. It stopped the jerking/hesitation and is back to full power. I recommend all of you to change the coils.

Note: I couldn't find which one was bad, so I bought all 8 and changed all 8 of the coils.

[bullittandy]

Great news! Glad to have another example to build a working theory.

Now, the key is to easily find the bad coil.....

[tt300z]

this is for mopar... How long has it been since you changed the ignition coils ? i am going nuts here with the same problem... at first it was just doing the missfire at idle but now its cutting out the power at around 2k to 3k .....

[Mopar]

tt300z,

I had the EXACT problems, jerking at stop light, hesitation from 1k to 3k rpm. I am on my 2nd day, the car is PERFECT. Not even a HINT of rough idle or hesitation. The car is MUCH MORE quicker now. Like brand new. I suggest you do the same and change all 8 plugs. I still have mine, but don't know which one is bad, because I changed all 8 of them at once. Also, make sure you have the NGK plugs.

Good Luck.

p.s. look at local junk yards. I found a 2000Q engine and bought the 8 coils and 8 injectors real cheap.

[bullittandy]

Does anybody know how to test a coil OFF the car?

[tt300z]

OK LETS MAKE THIS CLEAR....missfire at idle is IGNITION COILS period!!!!!

now if you have no power or stumbling at around 2k to 3k and no check engine and no codes IT IS YOUR MASS AIR FLOW when it goes out totally you will get TCS OFF.....SLIP.....AND SEVICE ENGINE SOON LIGHT...ALL AT ONCE.....the car will run like **** ..... NOW THE MISSFIRE THAT IS DRIVNG EVERYONE NUTS AROUND HERE IS IGNITION COILS "for sure"

hope this helps

[Mopar]

Well the jerking is misfire too (around 1k-3k) It was solved by changing the plugs. I HAD changed my MAF before hand thinking that it was bad.

[Chrisfrend]

My 97 Q45 (121,000 miles) started sputtering last weekend both idling and under power, throwing a code for cylinder number 1 misfire. Searched the forum and found a post from Q45tech and others recommending trying BG44 and stepping on it. Added the BG44 last Saturday night, drove only about 15 miles, and by Sunday morning the sputtering was gone. After about 150 miles put in more gas (Shell 93 octane) Wednesday night and everything was OK until last night when less severe sputtering started again. Added another bottle of BG44 with 3/4 of a tank and the sputtering went away almost immediately, within 10 minutes of driving. Took it to the shop today to check out (it also has some oil seepage from the valve cover gaskets). They checked out the #1 plug (NGK) and said it was fine (it has been in almost 50,000 miles) and that the seepage wasn't enough to cause any problems (also they slightly tightened the bolts on the valve covers). It seems pretty clear that whatever is causing the sputtering is affected by the BG44.

1) Does this problem sound like it is caused by the the fuel injector? 2) Should I take it on a long drive to clear it out this weekend or is this too risky? 3) Should I just drive it locally to see if the problem recurs so I don't get stranded or risk damaging the engine? 4) If the problem does recur should I add a third bottle of BG44 or is this much of this over a short period bad for the engine? Any advice would be appreciated. Thank you.

[qship96]

magic pill in a bottle wont correct mechanical fault-have you read ecm codes?

[Chrisfrend]

Code thrown was P0301 -- engine misfire in cylinder one. I realize the BG44 will not necessarily cure the problem but since it clears it up at least temporarily, am hoping might supply a useful clue.

[maxnix]

OK LETS MAKE THIS CLEAR....missfire at idle is IGNITION COILS period!!!!

Maybe yes, maybe no. It's not that simple as reading the previous posts in this thread alone will reveal.

[maxnix]

Code thrown was P0301 -- engine misfire in cylinder one. I realize the BG44 will not necessarily cure the problem but since it clears it up at least temporarily, am hoping might supply a useful clue.

Swap a coil and follow the failt codes.

[96Qowner]

Code thrown was P0301 -- engine misfire in cylinder one. I realize the BG44 will not necessarily cure the problem but since it clears it up at least temporarily, am hoping might supply a useful clue.

I've read every post on this syndrome over the course of three years. You're fortunate that you got a code for a specific cylinder. My advice would be to replace that coil.

It sounds like the coil on #1 is weak, and the BG 44K helps with combustion. I wonder if 8oz. of 44K is enough to change the volatility of the fuel mixture, or if it's simply having a pristine spray pattern that makes the difference.

[Q45tech]

The BG44k cleans the spark plugs and allows marginal coil [voltages] to fire the cleaner plug for a few weeks sometimes.

[Chrisfrend]

Thank you all for your advice. It sound like I should start by focusing on the #1 coil pack.

[bullittandy]

Maybe yes, maybe no. It's not that simple as reading the previous posts in this thread alone will reveal.

Every single person who has solved this problem including you has solved this problem by swapping a bad coil. It is that simple!!!!!!!!!!!!!!! (thread title)

"The BG44k cleans the spark plugs and allows marginal coil [voltages] to fire the cleaner plug for a few weeks sometimes. (Q45tech)"

This is the first real explanation for a temp solution.

[Chrisfrend]

I had the coil of the #1 cylinder replaced and the problem appears to have been solved. The Hitachi coil was about $113 at the local imported auto parts store. No hesitation or misfiring. Thanks again to all who offered their comments.

Modified by Chrisfrend at 5:05 AM 12/6/2007
Modified by Chrisfrend at 5:06 AM 12/6/2007

[96Qowner]

And thank you for posting back with the results.

[bullittandy]

And thank you for posting back with the results.

X2.-Andy

[dodiho]

Guys-we seem to be in the grove on this...finally there is a common "fix"-it seems -for these herky-jerky problems with the Y33...good that the code showed the faulty coil pak...hope we are all that lucky....thanks!

[jimi9746]

My Q is a 99T and I'm also in Marietta. I've also been having an intermittent skip" or "misfire" which is only at idle, and seems to be only after the car is warmed up.

Watching the RPM's when it happens, it appears be when the rpms get down to about 650 or so and as it skips the RPM's drop a bit each time...

What do you suggest?

Oh .... car is under 100,000 miles (maybe 93K plus or minus) ... service engine soon light just came on a few weeks ago. We don't drive the car daily, and bought it just 15K ago or so...

thanks

[maxnix]

What do you suggest?

Scan it with a good OBD II to see which cylinder(s) are misfiring. Then proceed to switching coilpacks, presuming plugs have been changed recently, and allowing non-maintained intake system may aggravate symptoms.

Of course, you have the luxury of taking your car to T-3.

[caricbrown]

I have been fighting a some what intermittent "sumbling, erratic idle, miss, low power, stall, etc" with one of my 1994 Q45s (160k) for a while now.

I already replaced the fuel pump, fuel filter, MAF, plugs, and just did a complete under plenum fuel line (to stop the leaks) and vacuum hose replacement. All injectors ohmed out.

I had almost given up, when today I decided to pull the plugs. Starting on the #1 side each plug seemed fine till I got to #5, it was wet and brown where all others were nice white with some gray. Hmm, maybe I have a weak #5 coil?