help please? vibration at idle in drive or reverse | Ford Explorer Forums - Serious Explorations

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help please? vibration at idle in drive or reverse

jr_96

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Joined
June 9, 2012
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City, State
Colorado
Year, Model & Trim Level
1997 ford explorer XLT
my 97 explorer with a 4.0 sohc engine will idle roughly. while sitting in drive or reverse my engine is causing a slight vibration but in neutral or park its smooth as can be. the rpms are around 700rpms when it vibrates. what would cause the random vibration, because some times ill come to a stop light and i feel the engine idle drop a little and then the vibration happens but yet if i push on the gas a little it goes away in the 900 range and doesnt return. its annoying and i seriously need help. ive checked spark plugs they are brand new and gapped correctly, the wires are checked and good, and the coil pack was replaced recently. if any one can help please que in. Thank you in advance, this is a great forum and has helped me and many others with problems and i couldnt thank enough of you for all that you do.
 



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A similar situation was happening with my truck. I suspected maybe the exhaust was vibrating causing the whole truck to seem like it was idling rough in gear. So as a test, I mounted a floor jack underneath the cats with a piece of 2x4 underneath. Then I raised the jack enough to put some pressure on the cats. I put my truck in gear and the vibration was gone. It turns out it was the cats vibrating. I think as a fix what I did was bend the cats slightly to lessen the vibration, also what I did was take a piece of 1/2" copper elbow and wedge it between the 2 cats so the vibration would " cancel" each other out, and it seemed to work.
 












A similar situation was happening with my truck. I suspected maybe the exhaust was vibrating causing the whole truck to seem like it was idling rough in gear. So as a test, I mounted a floor jack underneath the cats with a piece of 2x4 underneath. Then I raised the jack enough to put some pressure on the cats. I put my truck in gear and the vibration was gone. It turns out it was the cats vibrating. I think as a fix what I did was bend the cats slightly to lessen the vibration, also what I did was take a piece of 1/2" copper elbow and wedge it between the 2 cats so the vibration would " cancel" each other out, and it seemed to work.
Hmmm well when I open the hood and had my dad put it in drive the whole engine kinda shakes not bad but it does, we've tested the mounts there fine. Its not the Intake gaskets I've checked those when I replaced the thermostat and housing do to it cracking. I replaced the PCB valve and cleaned th. Tubes. I've had to raise the idle screw up to 800-900 rpm in drive because the vibration goes through the cabin. Now what the original iidle speed so I can try to set it back down after I figure iit out. Ill try the cats this weekend, ita weird because in park I get a weirs exhaust smell like its bad enough it'll make you cough, its not that rotten smell, my Buick regal had that. Maybe exhaust leak?
 






Hey did you ever figure this out? My 4.0 ohv does the EXACT same thing. It's driving me crazy. It happened a few months back when I removed and re-installed the exhaust. It feels fine in park and neutral but just like yours, it starts to shake in drive below 800 rpm. I just replaced my mounts so I can tell you for sure that wouldn't cause it. My motor still shakes a bit when I look at it even after the mounts. I'm guessing it has to be exhaust related because when I put pressure on the exhaust, the shaking is gone.
 






Bump to an old thread. I have a '98 SOHC Ex that started doing this exact same thing just about a week ago. While stopped in drive there is a vibration that I pretty much feel throughout the entire truck. The vibration seems like it is coming from the rear of the engine but I can also feel it underneath my feet as well as in the steering wheel. In fact I noticed the tail pipe also shakes. During the vibrations the tach does not fluctuate and the idle seems to be consistent - anywhere between 500-1,000 rpms. Sometimes, however, the idle will quickly drop below 500 rpms when shifting from drive to reverse or reverse to drive but it has not yet stalled out on me. Once I accelerate in either gear the vibration is gone and the truck runs perfectly normal. The check engine light is NOT on. I've had the exhaust, spark plus/PCV valve, and IAC replaced in that order over the past 3 years or so (only driven about 15-20k miles in that time). I may try putting pressure on the cats this weekend when the temps warm up a bit to see if that is a possible cause. Other than that I am pretty stumped, although I'm not sure where to check for the engine and/or tranny mounts. Also, any chance this an early symptom of the dreaded timing chain failure? All info is appreciated.
 






Torque converter clutch vibration.
Just slide the gear selector in "N" at stop lights to prolong the inevitable (not in "P").
Service the transmission (fluid and filter) as required by owner manual.
I also added in transmission fluid some friction modifier with modest results.

Worn out engine and transmission mounts will do a similar noise, by leaving the engine to "move" to much in the bay while TC is on stall mode - and therefore touching some exhaust shields...
 






Torque converter clutch vibration.
Just slide the gear selector in "N" at stop lights to prolong the inevitable (not in "P").
Service the transmission (fluid and filter) as required by owner manual.
I also added in transmission fluid some friction modifier with modest results.

Worn out engine and transmission mounts will do a similar noise, by leaving the engine to "move" to much in the bay while TC is on stall mode - and therefore touching some exhaust shields...

What exactly is the torque converter? I'm guessing a part of the transmission? I hope this isn't my problem, I can't afford a repair like that right now
 






So I finally got the chance to check this vibration and rattle out a little more. I had my father shift between all gears while I looked under the car with a flashlight. The source of the rattle almost seems like it is coming from inside the muffler but I can't visually see anything moving in that area. I didn't notice the cats or any heat shields moving either. The tail pipe was shaking a bit and I did noticed a small hole where it makes contact with the hanging bracket towards the rear. When I put pressure on the tail pipe and pushed it in to the left the rattle went away. Now my question is does shifting between P-R-N-D put different pressure on the exhaust possibly causing a shudder if something isnt right?
 






The engine and transmission moves/shifts slightly between D and N, because it sits on rubber mounts. So maybe that is enough to move the exhaust pipe?
 






I have the same thing happening. Shakes in D with the brake on and I even hear a buzzing sound. Lately, something hitting the floor pan when going over bumps and potholes. This is got to be the muffler but not sure if they are all related. I have a new transmission so I doubt it is transmission related.
 






So I finally got the chance to check this vibration and rattle out a little more. I had my father shift between all gears while I looked under the car with a flashlight. The source of the rattle almost seems like it is coming from inside the muffler but I can't visually see anything moving in that area. I didn't notice the cats or any heat shields moving either. The tail pipe was shaking a bit and I did noticed a small hole where it makes contact with the hanging bracket towards the rear. When I put pressure on the tail pipe and pushed it in to the left the rattle went away. Now my question is does shifting between P-R-N-D put different pressure on the exhaust possibly causing a shudder if something isnt right?

So it turns out the "small hole" in my tail pipe is a rather large hole right where the welded hook that connects to the rubber hanger is located causing the whole resonator pipe to shake. I had a new cat back system put on my Ex about 2 and a half years ago and this pipe is already rusted through. After doing both visual and online research it looks like my mechanic put on a Walker muffler and resonator assembly. The stainless steel muffler is in good shape but the resonator pipe is nasty. I see the Walker resonator assembly on rockauto for pretty cheap money but I'd like to get a stainless if possible so I don't have to go through this again in another two years. Any suggestions on a stainless resonator assembly? I'm not looking to delete the resonator or change the sound of the truck.
 






Here's a pic of the hole:

15797330724_d306312deb_z.jpg
 






Wow, salt and more salt...
 












Does anyone know where to get a stainless steel resonator and tail pipe assembly? I've searched high and low online and all I can find is the Walker part that is aluminized which obviously didn't last that long.
 






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