Severe hesitation/stuttering?

[ForYourOwnGood]

Since my car is almost brand new (I just passed 2000 miles yesterday) I had only given it full throttle a few times in 1st or 2nd for a short pull and then resumed normal driving.

Today I was merging onto the highway and really needed some power to not get squeezed off of the road by a semi so I mashed the pedal in 3rd and... nothing. The car sputtered and hesitated so badly I thought it was going to stall and I ended up having to run off on the shoulder.

No CEL flashing, although I don't know if that indicated knock on these cars or not. I was able to repeat the same serious stuttering a second time in 4th gear, both times were from ~3500rpm. I'll be taking it in whenever I can get an appointment but does anyone know wth might be going on with it? Only mod to the car is a catback. I've been feeling that it was severely down on power for a few weeks now but I thought that the PCM might have just been doing some kind of break-in cycle.

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[Juben]

The first thing I'd do is pull the plugs and check them out. If the gap has grown, it could be spark blow out. That sounds similar to what you've described.

 

[ForYourOwnGood]

The first thing I'd do is pull the plugs and check them out. If the gap has grown, it could be spark blow out. That sounds similar to what you've described.

I've had blowout before but not this bad, and usually only when the electrode had worn away to nothingness. I'll be pulling the plugs tonight anyways as my new brisk ones should be delivered today. I got plugs because the idle has been pretty ugly.

 

[Juben]

The plug gap from the factory seems to vary wildly, to say the least. It wouldn't surprise me if the gap was bad (too large). I had some rough blowout issues on a set of old plugs where the gap was just around 0.030-0.032. Ideally, you want to run the widest gap possible that can be done so without issues and I was trying to find the upper limit of the gap settings that I could use. During that testing, even 0.030 — top end of the factory gapping spec — caused issues. It almost felt like hitting fuel cut. It would operate normal under vacuum and light load, but as soon as the boost hit, it'd go to spitting and sputtering around like it only had 2 cylinders operating.

Depending on what levels of boost you're running, I'd set the gap between 0.026-0.028. I'd use 0.028 on factory boost levels and 0.026 on tuned boost levels. Hopefully, this will resolve your issues. Also, good choice on the Brisk. I've been running them lately and they've performed extremely well.

 

[ForYourOwnGood]

I just changed the plugs, gapped to .028.

The stock plugs were (from 1 to 4) .027/.025/.032/.032

I also did the age-old trick of stretching the spring a little so it gets better contact with both ends. Not sure how much of an improvement will be made until I go to work tonight as nothing around me is more than 25/35mph speed limit and lots of town traffic. It seems to not miss as much at idle though so I suppose there is that.

 

[Juben]

That 0.032 was probably the problem. That's a bit wide.

 

[ForYourOwnGood]

Well I gave it a 4th gear pull on the highway, no go. Still falls flat on its face stuttering/missing badly. I'll let it be fords problem now, along with the sirius radio that has been "updating" for two weeks.

 

[Juben]

Crap, I hate to hear that. If you take it to Ford, I'd throw the factory plugs back in temporarily. If they see them, I promise that they'll try to blame them and say it's something you've done. Dealerships are lazy and will use that against you.

 

[ForYourOwnGood]

Crap, I hate to hear that. If you take it to Ford, I'd throw the factory plugs back in temporarily. If they seem them, I promise that they'll try to blame them and say it's something you've done. Dealerships are lazy and will use that against you.

I saved them in the box I got the new ones in, little paper sleeves and all ;)

I've done the Ford warranty rodeo with 3 cars now, I know how they do things haha. Of course, with a high end car like the Cobra 15 years ago they didn't seem to care much and even gave you a free loaner car when it was in for service.

 

[TheLion]

Could be a bad coil. The winding on these coils are very fine, the insulation from winding to winding is an acrylic type of coating, which breaks down with heat or excessive flexing. However it's also prone to cracking, coils do come bad from the factory or can in some cases be affected by the assembly process.

You could try a set of Brisk RR14YS Silver racing plugs, their silver electrode design works in conditions iridium will not. Perhaps you have a bad tank of gas or water mixed in. Small stations typically have poor maintenance on their tanks (my dad's a service tech and has been doing pump work for 25+ years). Typically the water settles a the bottom as all tanks will have some leak, however the larger stations don't let their tanks get low enough to suck up water, the smaller stations tend to run their tanks much lower.

3500 RPM is near peak torque, so the turbo should be fully spooled up, making full boost. The issue would seem to be as Juben mentioned, failure of ignition as opposed to lack of fuel or air. The Brisk plugs can only do so much, however they are very well known for use in applications such as LPG, Nitro methane or other hard to ignite fuels, which makes them excellent for TDI applications.

 

[wildcatgoal]

Wait. You have like 2K on your car and it won't accelerate on the highway? And you're changing out spark plugs? Give that g'dam car back to Ford and get something else. Sorry but that is just not acceptable at all. There is no question this is a dealer problem.

 

[ForYourOwnGood]

Wait. You have like 2K on your car and it won't accelerate on the highway? And you're changing out spark plugs? Give that g'dam car back to Ford and get something else. Sorry but that is just not acceptable at all. There is no question this is a dealer problem.

Ford is going to have it on Thursday, we'll see what they say. I'll put the stock plugs back in before I go. I'll see if I can get a video of it on my way to work tonight but I haven't wanted to mess with it other than gently driving to and from work. Unfortunately I'll be going out of state for 12 weeks for work next week and I won't be able to do anything with the car until I get back.

 

[5.0yote]

Could be a bad coil. The winding on these coils are very fine, the insulation from winding to winding is an acrylic type of coating, which breaks down with heat or excessive flexing. However it's also prone to cracking, coils do come bad from the factory or can in some cases be affected by the assembly process.

You could try a set of Brisk RR14YS Silver racing plugs, their silver electrode design works in conditions iridium will not. Perhaps you have a bad tank of gas or water mixed in. Small stations typically have poor maintenance on their tanks (my dad's a service tech and has been doing pump work for 25+ years). Typically the water settles a the bottom as all tanks will have some leak, however the larger stations don't let their tanks get low enough to suck up water, the smaller stations tend to run their tanks much lower.

3500 RPM is near peak torque, so the turbo should be fully spooled up, making full boost. The issue would seem to be as Juben mentioned, failure of ignition as opposed to lack of fuel or air. The Brisk plugs can only do so much, however they are very well known for use in applications such as LPG, Nitro methane or other hard to ignite fuels, which makes them excellent for TDI applications.

He would have a misfire CEL if any plug was not firing. Let Ford sort it out, (2000 miles and this behavior is not acceptable) hopefully its something really silly like a vacuum leak, or whatever and not have to lemon law it.

 

[ForYourOwnGood]

OK so I got it back, they changed the oil and did the basic service and checked around a few things, they ended up recalibrating the pedal and the throttle and it feels much better now. I remember reading something about pedal calibration (possibly on this forum) once they said it.

Drove it to work last night and it felt fine in 3rd/4th pulls, I guess what it was doing was opening and closing the throttle rapidly because the pedal wasn't being read correctly or the stepper motor for the throttle plate wasn't responding to the demand in a linear fashion. They said if the problem persists they will change the throttle body most likely.

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