hi guys,how are ya?ive got a 1gen with 3.0lv6 found in your 2nd gen,its also a 5speed,but il try exlplain the problem that im having.the car seems to jerk alot,but i dont think its the engine,the engine works fine no problems,but if im doing say like 50 0r 60kays,and the road dips on a downward slant in 4th or 5th the car jerks.it will stop jerking if i give it more gas,or if i take my foot off the accelerator,thing is it doesnt do it on a steep climb or steep decend,it will if im at a steady cruz in second(25 or 30 kay)like when im looking for a car park at the mall,which is a flat surface.i know its not the engine,i had it for a year when it was an auto no problems at all,and also engine has been tuned and serviced.however i noticed the little shock on the rear engine mount,and thought that maby the engine is rocking fourth an backward,so decided to take it off.when i did i could compress it in and out easily wth my hands.no way was i going to buy a new one,so i wielded it solid.you can feel a bit of vibration in the cabin,but hasent made the slightest bit of difference.this problem wont stop me driving the car,but its a pain in the butt i have to say!.so any feed back on this issue would be a big help cheers!

What sort of RPM is the engine doing when this happens? If it's below 1500, then it's just too low an rpm for that road speed and you'll need to shift down a gear.
Basically the ECU is switching between idle and go mode and that causes some backlash or jerking.
At least that's my experience.

What sort of RPM is the engine doing when this happens? If it's below 1500, then it's just too low an rpm for that road speed and you'll need to shift down a gear.
Basically the ECU is switching between idle and go mode and that causes some backlash or jerking.
At least that's my experience.

its a tricky one,it still does it when im traveling at 60 ks in 4th or 5th gear on a downward slant.its the only time it does it

My car has a similar shuddering when it's running out of fuel. When my fuel is very low and I'm cornering or going down a slope, it shudders as engine is starved of petrol. that's when I know i have to switch to LPG. :-)

Have you changed the fuel filter recently or used a fuel system cleaner?

Drive shafts! First gen is known for having sloppy drive shaft joints that will give you that problem on light throttle. Also check your TPS settings.