High RPM Miss/Sputter

[douglee25]

I seem to have developed a miss that is noticeable in 3rd gear at WOT on my '97 M3. I don't feel the miss in 1st or 2nd. The miss is apparent around 5500 - 7000 RPM's. It occurs very quickly but it's definitely noticeable.

I changed the plugs 3 months ago. I made sure to put dielectric grease on the boot ends when I reassembled and anti-seize on the plug threads. The car does not possess any other symptoms and no codes came up when I scanned it.

I'm assuming it's ignition related as it occurs in the upper RPM range. Is there anything else to look for besides cracked plug boots and or carbon tracking? Maybe I put too much anti-seize on the plug threads and it's arcing there? Replace plugs for assurance? Replace plug boots? Any help would be appreciated. Thanks again.

Doug

[Bimmerforums]

How many miles do you have? Replace your fuel filter, I noticed a slight improvement when I had the same problem. Didn't fix it though but thats probably related to my CEL; P0153- slow or delayed response time from the o2 sensor even though I changed them

[douglee25]

How many miles do you have? Replace your fuel filter, I noticed a slight improvement when I had the same problem. Didn't fix it though but thats probably related to my CEL; P0153- slow or delayed response time from the o2 sensor even though I changed them

I have 102k on the car. I replaced the fuel filter in June. I am going to tear into it this morning and have a look at the plugs and coils. I will also check fuel pressure as well.

Doug

[douglee25]

Well I pulled the plugs and they all looked ok, but for $1.98/plug I replaced them. I gapped them to 0.032" and I also replaced the boots on the coils as they were slightly cracked from numerous heat cycles I suspect.

I went out and tested it and I felt the car hesitate again around the 6000 rpm mark or so.

I am going to try testing the fuel pressure tomorrow and see what it reads. I may run the tank low and fill up with 93 octane. I would be curious if the computer is retarding the timing somehow and maybe I'm feeling that for some reason? I doubt it but I'll give it a shot. Nothing is worse than having a problem that a computer won't throw a code for and you basically throw parts at the car in an attemp to fix it.

Any other recommendations?

Doug

[Bimmerforums]

Maybe it could be the coils

I would like to know the culpret as well..

[M3Rob95]

My car is doing the same thing..

Almost exactly..

It is not throwing any codes as well

My plugs were also recently replaced so could it be the coils?

[thejlevie]

At 102k, your pre-cat sensors could be a contributor to the problem as they should be changed no later than 100k. They usually have aged enough to justify replacement by 80k.

If the car has an oiled air filter (typically part of a CAI) I'd suspect contamination of the MAF.

[douglee25]

At 102k, your pre-cat sensors could be a contributor to the problem as they should be changed no later than 100k. They usually have aged enough to justify replacement by 80k.

If the car has an oiled air filter (typically part of a CAI) I'd suspect contamination of the MAF.

No CAI but I could clean the MAF for kicks anyway. I thought it could be O2 sensor related but that's usually low rpm stuttering, etc. This is high rpm hesitation, although anything is possible.

I'm trying to avoid fixing the car by just throwing parts at it. Maybe if I drive it longer, the problem will get worse and hopefully throw a CEL. This hopefully would point me in the right direction anyway.

Doug

Edit: In my mind, the list of possible fixes are (in no particular order):

1. Bad gas/low octane gas
2. Coils
3. O2 sensors
4. Dirty MAF
5. Fuel Pump
6. Fuel Pressure Regulator
7. Plugs - Complete
8. Coil Boots - Complete

[Balthazarr]

High rpm is usually an ignition issue.
Suspect the coils now since you inspected the other parts.
Pray it ain't the harness.

[pioneer416]

I have the same problem, i too replaced the fuel filter, plugs, cleaned the MAF, i think the next step is either coils or O2 sensors. I actually went to the dyno when these sysmptoms first started to occur, and it showed up on the graph. To the op is this problem random in the rpm band like mine? I've been trying to solve this problem before i have to throw alot of money at it, i just dont want to over look anything simple



^ You can clearly see the skips, and it is a diff rpms everytime

[thejlevie]

Notice that the engine is running rich through the bad where the misfires are occurring. That would tend to point to O2 sensors or the MAF.

[Bimmerforums]

I have the same problem, i too replaced the fuel filter, plugs, cleaned the MAF, i think the next step is either coils or O2 sensors. I actually went to the dyno when these sysmptoms first started to occur, and it showed up on the graph.

I had the exact same problem . After changing the fuel filter it helped a little bit but then started happening again. The 02 sensors didn't make much of a difference either. It's weird though, the last couple of days the car has been running amazing and no misfires or anything.

[epj3]

My car is doing the same thing..

Almost exactly..

It is not throwing any codes as well

My plugs were also recently replaced so could it be the coils?

As does mine, but not all the time. My entire ignition/fuel systems are new.

[M3Rob95]

I have the same problem, i too replaced the fuel filter, plugs, cleaned the MAF, i think the next step is either coils or O2 sensors. I actually went to the dyno when these sysmptoms first started to occur, and it showed up on the graph. To the op is this problem random in the rpm band like mine? I've been trying to solve this problem before i have to throw alot of money at it, i just dont want to over look anything simple



^ You can clearly see the skips, and it is a diff rpms everytime

Mine seems to skip just like that..

You can feel it throughout the whole car (like the diff etc)

How did you all go about cleaning the MAF?

Has anyone had these problems and actually fixed them???

[pioneer416]

Mine seems to skip just like that..

You can feel it throughout the whole car (like the diff etc)

How did you all go about cleaning the MAF?

Has anyone had these problems and actually fixed them???

You can get an electronics cleaner that leaves no residue and cleanit, i think i might do that again since i recently re-oiled my CAI. When i go home this weekend im goin to go through as much as i can, inspect all boots for cracks, plugs, and maybe even take the manifold off and check everything under there. These skips are really felt in 3,4,5th gears, i think its because of one of two things. Either we go through 1 and 2 gears too fast to feel anything, or that in extended WOT where the mph's dont climb as fast like 3,4,5th something cannot keep the spark/ignition up and skips as a result. Hope that makes sense

[gilly]

Couldn't this still be a gas quality issue? I know in Oregon they change the gas as winter roles around and then bring out the "good" gas when spring/summer kicks in.

My .02

[pioneer416]

Couldn't this still be a gas quality issue? I know in Oregon they change the gas as winter roles around and then bring out the "good" gas when spring/summer kicks in.

My .02

I doubt it, i think most of us that have this problem have been experiencing for some time, and my dyno runs were conducted on 7/21...so in the heart of the summer. and i get my gas at the same place, and only recently do i have these issues. But who knows maybe ill throw some marvel mystery oil in my tank.

[Bimmerforums]

Ya I highly doubt its a gas issue because my dyno was in May.

[epj3]

My next step is crank and cam position sensors...

[pioneer416]

My next step is crank and cam position sensors...

If those sensors fail don't they throw codes, im pretty sure they do

[thejlevie]

Yes, you'd get a fault code for a bad cam or crank position sensor.

[M3Rob95]

You can get an electronics cleaner that leaves no residue and cleanit, i think i might do that again since i recently re-oiled my CAI. When i go home this weekend im goin to go through as much as i can, inspect all boots for cracks, plugs, and maybe even take the manifold off and check everything under there. These skips are really felt in 3,4,5th gears, i think its because of one of two things. Either we go through 1 and 2 gears too fast to feel anything, or that in extended WOT where the mph's dont climb as fast like 3,4,5th something cannot keep the spark/ignition up and skips as a result. Hope that makes sense

Makes perfect sense..

My is doing the exact same thing.. Pretty hard to describe imo

Looking for the fix!

[epj3]

Yes, you'd get a fault code for a bad cam or crank position sensor.

If it flat out failed it would throw a code. There's a chance it may be making an occasional bad pickup. Could be heat, vibration, etc. related - though I'm not an expert on hall sensors.

[jayzx7]

i'm having the same problem and it's been awhile now. i've heard some body else say that it was a sensor too. would like to know for sure.i'm bringing mine to a shop hopefully this week for some work and i'm going to ask him to check it out

[pioneer416]

i'm having the same problem and it's been awhile now. i've heard some body else say that it was a sensor too. would like to know for sure.i'm bringing mine to a shop hopefully this week for some work and i'm going to ask him to check it out

thatd be awesome if you got a direct answer/fix, i was maybe thinking pre cat O2 and maybe knock sensors...but idk. my car is considerably slower with all this i feel like its pulling timing and knocking, and i kno i have good gas so some sensors not keeping up or simply isnt good anymore...thats my thoughts at least.