About two weeks ago I noticed that when I would start my 04 na it would jump forward abruptly, unlike normal when it eased forward. Then about a week ago I noticed it surging forward when slowing to a stop. Now on acceleration in 2nd it surges forward and in third and fourth it has a very bad vibration (so much it rattles the rear window). Now if I ride in 4th the vibration comes and goes. Also when it is vibrating I almost have to put the petal to the floor to get it to move. It appears it is getting worse. Opinions?

its an automatic, no mods, 60k miles

 

Short answer based on what your describing, I'd lean towards the transmission.

If it idles okay, and rev's smoothly while out of gear (Neutral), that wouldn't completely remove an engine issue, but it would be a good sign.

I know the Service interval on the Manual is stated at 100k miles, but I believe the Auto comes in under that, maybe it's 50k miles.

On my Auto cars in the past, I would typically have a Tranny Service done at least every 40k or 3 years, whichever came first.

It might be as simple as cleaning the screen, and refreshing the Tranny fluid...