Hey all,
I have posted a good bit on the "other" boards and have a similar thread going over there, but am in need of good advice and know there are some great minds at work over here as well.
Here's the rundown:
-I have a shuddering vibration that varies by speed, temperature, and the grade of the road (uphill/downhill)
-The vibration is generally worse in cooler temperatures, and is almost non-existent when the ambient temperature is above 85-90F.
-The vibration affects the entire vehicle and can be felt in the steering wheel, seat, and every other portion of the interior.
-The vibration, when it exists, is particularly bad when traveling between 60 MPH and 80+ MPH. At lower speeds it can be felt, but is not nearly as noticeable.
-The frequency varies with speed, and does not change (in frequency) when the car is engaged in a different gear. If I shut off OD, the vibration increases somewhat in amplitude but the freuency stays the same.
-The vibration is markedly worse when traveling even slightly uphill, especially when the engine is loaded but the transmission is not forced to shift (meaning that it stays in OD but throttle is increased to maintain speed). When traveling downhill, the vibration is generally worse when I let off the throttle.
-I have observed the steering wheel shaking vertically up and down when the shudder exists, rather than rotating side to side (such as when rotors are warped). When I have a beverage stored in the cupholder, the top of the container can be observed moving back and forth. The frequency of these movements matches what I feel in the rest of the car.
-The vibration exists with both sets of wheels/tires that I have for the car. The consist of 16" snowflake wheels with BFG Traction T/A 225/60/16 tires and 17" Cobra-R wheels with BFG G-Force T/A 255/50/17 tires.
So far, I have done the following to remedy the issue:
-Trans fluid has been changed to Mercon V, filter has been changed, and a 45k GVW trans cooler has been installed.
-The stock driveshaft was changed to a known-good '93 Mark shaft with brand new u-joints and a balance job. The missing spline in the yoke was aligned with the mark on the output shaft.
-Replaced front rotors/pads with brand new NAPA replacements.
-Replaced front hubs/bearings.
-Replaced front brake calipers.
-Replaced almost entire front end: lower control arms, upper control arms, strut rod bushings, outer tie rod ends.
-Four wheel alignment on a calibrated Hunter machine by an experienced tech in a Lincoln dealership.
-Tire air pressure has been maintained at several different pressures ranging from 28PSI to 32PSI. The best results have been achieved at 31PSI, but the shuddering has by no means gone away.
I have owned the car for about 10,000 miles. I changed the spark plugs, air filter, fuel filter and all fluids within the first 2,000 miles of ownership. The car has a very slightly rough idle in neutral but runs like a top when in gear and throughout the RPM range, and has plenty of power on tap when I need to pass on the highway etc. I do get a very occassional torque converted shudder, but it almost never happens now after all the work I've done. Is it possible for a miss to show up only in these conditions? The shudder certainly feels like it's somewhere in the drivetrain, and if changing/re-gapping the plugs will fix it then it'll be the first thing I do on Saturday morning. I only use Mobil/Shell/Sunoco for gas after a few bad run-ins with discount brands - never again will I use anthing else. I should also mention that I have checked nearly every bushing in the driveline and they are all in great shape - no cracking or splitting anywhere on the entire car.
I have checked all of the PCV/vacuum hoses, and they appear to be in pretty good shape. The two curved hoses that connect to the upper intake manifold are beginning to look cracked, but I have sprayed the area with starting fluid in the past to check for leaks and had a negative result. When I changed the spark plugs I did notice a bit of oil on a few of the coil boots, though not enough to flood the spark plug. A few of the boots also had a brownish residue on them, which I chalked up to the oil leaks. All of the boots are in great shape though, absolutely no cracking whatsoever. You've got me wondering how much of a difference I'd see if I changed out the coils, though that's more expensive than I can afford to "try" at this point.
The other thing that sticks out to me is that the vibration does not just exist upon acceleration, but also during downhill coasting. This (to me) would appear to rule out a slight miss but perhaps I am wrong. Another note of importance: I have never, ever experienced a Check Engine light in this car.
Thanks for any help you can provide.
-Domenic
I have posted a good bit on the "other" boards and have a similar thread going over there, but am in need of good advice and know there are some great minds at work over here as well.
Here's the rundown:
-I have a shuddering vibration that varies by speed, temperature, and the grade of the road (uphill/downhill)
-The vibration is generally worse in cooler temperatures, and is almost non-existent when the ambient temperature is above 85-90F.
-The vibration affects the entire vehicle and can be felt in the steering wheel, seat, and every other portion of the interior.
-The vibration, when it exists, is particularly bad when traveling between 60 MPH and 80+ MPH. At lower speeds it can be felt, but is not nearly as noticeable.
-The frequency varies with speed, and does not change (in frequency) when the car is engaged in a different gear. If I shut off OD, the vibration increases somewhat in amplitude but the freuency stays the same.
-The vibration is markedly worse when traveling even slightly uphill, especially when the engine is loaded but the transmission is not forced to shift (meaning that it stays in OD but throttle is increased to maintain speed). When traveling downhill, the vibration is generally worse when I let off the throttle.
-I have observed the steering wheel shaking vertically up and down when the shudder exists, rather than rotating side to side (such as when rotors are warped). When I have a beverage stored in the cupholder, the top of the container can be observed moving back and forth. The frequency of these movements matches what I feel in the rest of the car.
-The vibration exists with both sets of wheels/tires that I have for the car. The consist of 16" snowflake wheels with BFG Traction T/A 225/60/16 tires and 17" Cobra-R wheels with BFG G-Force T/A 255/50/17 tires.
So far, I have done the following to remedy the issue:
-Trans fluid has been changed to Mercon V, filter has been changed, and a 45k GVW trans cooler has been installed.
-The stock driveshaft was changed to a known-good '93 Mark shaft with brand new u-joints and a balance job. The missing spline in the yoke was aligned with the mark on the output shaft.
-Replaced front rotors/pads with brand new NAPA replacements.
-Replaced front hubs/bearings.
-Replaced front brake calipers.
-Replaced almost entire front end: lower control arms, upper control arms, strut rod bushings, outer tie rod ends.
-Four wheel alignment on a calibrated Hunter machine by an experienced tech in a Lincoln dealership.
-Tire air pressure has been maintained at several different pressures ranging from 28PSI to 32PSI. The best results have been achieved at 31PSI, but the shuddering has by no means gone away.
I have owned the car for about 10,000 miles. I changed the spark plugs, air filter, fuel filter and all fluids within the first 2,000 miles of ownership. The car has a very slightly rough idle in neutral but runs like a top when in gear and throughout the RPM range, and has plenty of power on tap when I need to pass on the highway etc. I do get a very occassional torque converted shudder, but it almost never happens now after all the work I've done. Is it possible for a miss to show up only in these conditions? The shudder certainly feels like it's somewhere in the drivetrain, and if changing/re-gapping the plugs will fix it then it'll be the first thing I do on Saturday morning. I only use Mobil/Shell/Sunoco for gas after a few bad run-ins with discount brands - never again will I use anthing else. I should also mention that I have checked nearly every bushing in the driveline and they are all in great shape - no cracking or splitting anywhere on the entire car.
I have checked all of the PCV/vacuum hoses, and they appear to be in pretty good shape. The two curved hoses that connect to the upper intake manifold are beginning to look cracked, but I have sprayed the area with starting fluid in the past to check for leaks and had a negative result. When I changed the spark plugs I did notice a bit of oil on a few of the coil boots, though not enough to flood the spark plug. A few of the boots also had a brownish residue on them, which I chalked up to the oil leaks. All of the boots are in great shape though, absolutely no cracking whatsoever. You've got me wondering how much of a difference I'd see if I changed out the coils, though that's more expensive than I can afford to "try" at this point.
The other thing that sticks out to me is that the vibration does not just exist upon acceleration, but also during downhill coasting. This (to me) would appear to rule out a slight miss but perhaps I am wrong. Another note of importance: I have never, ever experienced a Check Engine light in this car.
Thanks for any help you can provide.
-Domenic
