So my fit has roughly 65k miles on it and I already had my valves adjusted about 5k miles ago to fix a misfire problem that I had. But now over the last few weeks I've been noticing that after the car warms up it has this pulsating idle when I come to a stop in drive, you can feel it vibrating on your back as you sit in the drivers seat. The pulsating comes every second 'vrmm.. Vrmm.. Vrmm.. Vrmm..vrmm' like that. During the pulsation there is NO change in rpm's you can only feel it. I only use high quality mid grade gasoline. I'm guessing it might need a new battery because I think it still has the original battery? . Or maybe coil packs? I need your help guys. Thanks in advance.

 

Battery going dead will NOT make for rough idle.

Find a buddy with a code scanner or go to autozone or pep boys type place and see if it is throwing any MILs.

Coilpacks USUALLY effect high speed/load not idle.

Can you tell it all the hoses were hooked back up correctly after the valves were done because it sounds more like a vacuum leak. Can you hear any hissing under the hood with the engine running?

 

Leaking vacuum hose somewhere perhaps?

 

I can hear a his under the hood but only when under load around 2500- 3k rpms but im thinking that sounds more like induction noise. I didnt even consider checking for a vacuum leak(fuck) .

 

i've had the same problem and i have a 2008 fit base automatic transmission as well. a guy that did my oil recommended a transmission fluid change for 70 bucks. is it worth a try?