Vibration when accelerating

[dreameral]

I have a 2000 xl. When I accelerate, usually in the 40-60 km.h range, there is a vibration. I can feel it through the gas pedal. It is very slight but there. I have replaced the air filter and ran sea foam through the brake booster but no difference. THere is 166,000 km on the car (About 100,000 miles). Dealer put a new timing belt on at 160,000. Could this be spark plugs. Dealer wants 200.00 to replace iridium plugs. Ouch! How do you tell if it is the mounts and how much are the replacements.

[car5car]

Check ATF, suspension, balancing

[Eurobob]

Does the vibration stay around when you level off your speed in that 40-60km/h range? If it vibrates under acceleration and goes away when you let off of the gas, i would take a close look at a cv shaft. I had a car that vibrated only under acceleration, the shaft was my culprit.

[dreameral]

yes it seems to level off but lately when cold it vibrates at idle and goes away when warm, then only when I accelerate