Sometimes and sometimes not, my maxima (automatic) thumps every 2-3 seconds or so. It's weird because one day it could be normal and no thumping but the next day it could be thumping. I believe it could the spark plugs or coils. Might be misfiring. Also feels like it's coming from the front. Could it be my transmission? The thumping has been going on for months I think. My dad told me not to worry about it but it's been annoying me so now I want to get to the bottom of it. Anyone know why?

 

Can you capture a brief video and post it?
Pull the codes for the heck of it.

 

I found the issue! It was the coil packs.

 

So you swapped all the coil packs or one at a time?

I believe I know the issue you are having, I had it a couple years back, went away and has recently returned. It's most noticeable in gear at a stoplight, engine will buck slightly with rpms dipping slightly then returning. Immediately goes away if in neutral or park.

 

Glad you got it figured out. Thanks for coming back and providing an update.