need help with 01 pathfinder

[tonyljeff]

i have a 01 pathfinder 3.5le. it has 140,000 miles on it when i brought it it had 134,000 miles on it. latley sometimes when i start it up it shakes not bad but you can notice when it does it. since i had it it done it about five times. i know i have to changed an downstream o2 sensor could that have something to do with what is going on. i use super unleaded so i don't have a clue. if someone had or are having similar problems or know what the problem is please post thank you.

[Adnan]

did you look at the spark plugs?mine felt kinda like sitting on a washer when i bought it it would kick in everyonce in a while when idling

[pathfinder9035]

check sparker and coils and maf. those were the main problems for the 01 pathfinder. do the cheap stuff first of course