2003 outlander shaking problem
 

2003 Outlander 100K miles

when I drive on uphill at 40-50mph, the car will shake intermittently,

like shaking---stop shaking for seconds---shaking----stop shaking for seconds---shaking. pretty big...

I do not know whether it is related with the timing belt change, or not. I think I found this problem after I got the timing belt and water pump changed. But I am not very sure.

any comments for this? thank you!