2000 Mercury Cougar 60mph+ vibration

I would suspect a tire balance or air pressure problem. Have an alignment shop check the suspension, ball joints, tie rods, CV joints, brake caliper slide pins. Have the alignment shop check camber, toe and caster.

Whenever you store a vehicle you should add a fuel stabilizer to the gasoline to prevent varnish build-up in the fuel system.

yes, I forgot to mention, the tires had nitrogen in them, but i removed that and replaced it with air and made sure all the tires had the exact same recommended tire pressure (40psi in this case) and that did not help. I had a shop check the all the front end components (yesterday), although I am not sure if they checked the camber, toe and caster. But anyways, they could not find anything. They said that they "think" its the aftermarket rims and tires (even though i explained to them that it was doing it with the stock wheels and tires). Also they said that they "think" also that it could be the aftermarket crossed-drilled and slotted rotors I have on there (even though they meet OEM spec, and do not cause any vibration upon braking). Needless to say, they did not help me much other than to tell me they are not sure what is causing the vibration. I have an appointment today to with a different, more reputable shop, that has a "on the car tire balance system" or something like that. When I called the shop to make the appointment for today, the guy said that he has never met a vibration problem that he could not fix. So hopefully he hasn't met his match his with my car...

Also, on a side note: I should have added the fuel stabilizer upon storing the car, because for about three weeks after I got it out of storage it was hiccuping and burping and even stalled a few times at idle, but after a few weeks, and then on after, it runs great.

Tylermax......
keep me posted on your progress, I too am having the same problem but at 70mph. The shop cant seem to give me an answer.. I had tie rods, control arms new brakes, rotors and calipers. Still does it.
The shop didnt have a wheel balance machine so I had to get it done elsewhere and it still didnt work.
Thanks
Kevin

okay well I took it to a shop yesterday and they said that everything on my front end looks good except the drivers side control arms look pretty bad and the passengers side control arm is somewhat bad. He said he is "pretty darn positive" that this will fix my problem. I hope so because it's like $685 with parts and labor to fix both control arms in front. Could this be the possible cause? and is $685 a fair price? They said that they had to get those parts from the Mercury dealer because nobody else carried them, and they charge $75 an hour for labor, which is pretty reasonable in this area.

CarPros... please give a quick reply if possible before and let me know what you think before I make a $685 mistake! thank you.

it could be the control arms, and that could explain the pull to the right.

the whole front end has been checked, but has the back end been checked?

dont overlook the rear end, would look at that first, make sure the tires are properly tightened and such, check stabilizers bushings and the likes in the rear end.

if those are all good then your going to have to go for the control arms. sounds like not too much left. any of your brakes dragging causing the pull to the right? check them after driving a few miles. do any of the rims get hotter then the rest? could be a bad rotor or brake issue causing the vibration. seen it before.

If when you mean dragging, do you mean touching of the pads and rotors while not applied? I am pretty sure they are not touching, because I used to have a car that did touch once I got the brakes changed and I could definitely hear it while driving.

I don't think the rotors are warped because it does not shake when I apply the brakes. Would it still be possible to get a warped rotor that doesn't shimmy the car when I apply the brakes, but still cause vibration at interstate speeds? When you say bad rotor do you mean warped?

i highly doubt that is causing your problem i was saying moreso as they said the sloted rotors that you installed could cause that, and i was saying the only way that could happen would be bad/warped rotors.

no shimmy when stoping, doubt its the brakes.

ok, I went ahead and paid to get the control arms fixed, and the car runs like a dream now! no vibration at all. The shop said the lower control arms experienced dryrotting, likely from sitting in storage for six months.

gllad to hear you have gotten the car running like a dream again, sorry to hear it was the control arms, an expensive little item.