Question about bucking in the rain

[Pantherfreak]

Greetings folks. My '04 MM started acting up for the first time ever the other day during a 20-ish mile highway run in very heavy rain, and I'm trying to narrow down the possible cause. It's got 195k clicks on it. Upgrades are a JLT cold air, BBK throttle body, Steeda underdrives (minus alt pulley), Lidio tune, and a JLT oil catch can.

When accelerating moderately at highway speed (say from 110 km/h to 120 km/h) I started to experience a "bucking" sensation. As I said, this was in heavy rain. Not overly violent, and at a steady cruise it doesn't do it at all. On cruise control, it will do it a bit if you hold the accel button down. But if you just tap the accel button once, it doesn't do it. I don't think it's a transmission shudder, which I've experienced in my '94 CV. But you can feel it clearly in the throttle. The car itself doesn't seem to be affected - you just feel it in the throttle. I've read the term "cutting out", but I don't really know what that feels like.

I've been researching the site, and it seems like the cops and plugs might be the most likely cause. I changed the plugs 4 or 5 years ago, but I believe the cops may be original. I've had the car since 45k clicks, and don't recall changing the cops. I've also read a few posts about the TPS, IAC, crank and cam sensors. It never stalls or even comes close, so I don't THINK it's the IAC. There is a bit of roughness to the idle, but nothing major.

So I'm looking for any input at all as to whether I'm on the right track here thinking it's the cops and/or plugs. I suspect the heavy rain allowed water into an area that has degraded with time and mileage. I have been working from home due to covid, so my daily 45 mile commute to work has not happened all summer. Although I drive it often, I haven't been commuting with it much. Perhaps that is a factor as well? Also, I have driven it in dry weather since the big rain and it is still "bucking" at highway speeds. Also, it doesn't seem to affect heavy throttle, although the power may be down a bit.

Any assistance would be greatly appreciated.

[Turbov6Bryan]

I only had that problem once and it was raining really really hard in the car with buck I was actually the trash control turning on and off when she would see the light come on the dash. Driving in heavy rain you really shouldn’t use a cruise control anyway. My other Marauder without the supercharger on it with buck and dry climate with the torque converter locked up in fourth gear, slowing down and really lugging the engine down really low RPM it would Bockman, once I shut off overdrive you would read the engine up higher and stop barking. That ended up being one bad coil. American muscle cells the coils and they are about $300 US. I found some really cheap coils to use as testing tools to rule Out wiring issues. I was able to purchase eight made in China coils for $30 shipped and that fix the problem

[Turbov6Bryan]

I really love talk to text, it makes things interesting

[Comin' in Hot]

it sounds like a bad coil(cop), and could be mistaken for partial throttle transmission shutter.

[blazen71]

I really love talk to text, it makes things interesting
I just chalked it up to day drinking.

[MyBlackBeasts]

Dupe..................

[MyBlackBeasts]

I only had that problem once and it was raining really really hard in the car with buck I was actually the trash control turning on and off when she would see the light come on the dash. Driving in heavy rain you really shouldn’t use a cruise control anyway. My other Marauder without the supercharger on it with buck and dry climate with the torque converter locked up in fourth gear, slowing down and really lugging the engine down really low RPM it would Bockman, once I shut off overdrive you would read the engine up higher and stop barking. That ended up being one bad coil. American muscle cells the coils and they are about $300 US. I found some really cheap coils to use as testing tools to rule Out wiring issues. I was able to purchase eight made in China coils for $30 shipped and that fix the problem



:?: Bwahahahaha!!! Whatcha drinking my friend?!? Please share!!! :beer::drink:

[justbob]

The problem is your driving a Marauder in the rain..


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[Pantherfreak]

So, just a follow up, for anyone who is interested. I ended up purchasing new COPs from MSD (comparable quality to Ford, half the price) and a set of new plugs.

I found no water in any of the wells, and the plugs all had normal wear and colouring for their mileage. Most of the COPs looked okay as well, except for 2. The rearmost COP on each bank had a bunch of white, chalky residue all around them where they sat in/on the wells. The residue didn't extend down any further than about an inch. But that tells me there was water intrusion in those 2 points. It was that white, flaky corrosion you get on exposed aluminum. So it seems that water was getting in at the rear of each head where the COP wiring bundle comes in.

I cleaned up all the white corrosion, used the normal amount of dielectric grease on the boots at the plug ends, and applied the dielectric grease on the rubber gasket all around the underside of the COP cover (mine are Ford Motorsport covers, because they're pretty). I test drove it for a while, and the problem appears to have gone away. No more bucking, and the idle has smoothed out a bit.

So, another example of what happens when your COPs get wet. I never used grease on the COP covers when I first installed them...lesson learned.

And to justbob - I agree. Normally I don't take it out in the rain, but sometimes it just happens. It's actually good that I did, or I wouldn't have found the water intrusion at the COPs. It had been like that for a while, I suspect.

Anyway, thanks to all for the input!

[justbob]

MSD is not comparable to Motorcraft besides looks.

There has been plenty of early failures on those and Accel, some being right out of the box. Not even gonna mention the knock offs.


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[offroadkarter]

MSD is not comparable to Motorcraft besides looks.

There has been plenty of early failures on those and Accel, some being right out of the box. Not even gonna mention the knock offs.


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Yeah I'm sorry but ever since I had a MSD ignition coil die on my bronco after 5000 miles I really question MSD quality. Bob is right, aftermarket COPs for Fords are always a major crapshoot. Granatellis are also on the "avoid" list.

[Mebot]

Motorcraft for COPs. Seriously. Look up threads from the past (which is hard to do, i know,) but never heard a complaint from anyone using Motorcraft

[MyBlackBeasts]

Motorcraft COPs only. Get a set from Sparta (a supporting vendor!):
http://spartaperformance.com/svt-4v-ignition-coil-set/

[Pantherfreak]

Yeah - that was my intention, but a crapload of big bills all came in at the same time, so it was strictly a money decision. I've had MSDs on a 2V in my '05 MGM for a few years and so far so good. But I realize it is a crapshoot.

[88LTDCV351]

Last time I had bucking on the Marauder, I just replaced the plugs. It's been fine since.

As far as MSDs, never had a problem with them. However, for the longest time, I know on their site, they listed the SOHC coil for the Marauder so you had to pick the Mach 1 one to get the right one.