Hi, Im trying to get some feedback. I have an 08 fit with 120K miles. It just started surging (or anti-surging if that is a term) when it got cold a couple weeks ago (below freezing temps). It lasts for ~5-10 minutes (or about 4 miles) and then it purrs just fine. The surging/hesitation is cyclic of about 3 seconds and lessens in intensity but stay the same frequency as it gets closer to going back to normal running. I did the valves and cleaned the throttle body, and it did not fix it. Changed the air filter, nada. So my list of things it could be include:
-bleed coolant
-PCV valve
-MAP
-'new' throttle body
-engine coolant temp sensor
-EGR valve
-Fuel pump
-fuel filter

Any help would be GREATLY appreciated!!

 

valve clearance adjustment...

 

I had already done that (that is what I meant when I wrote that 'I did the valves')... didn't fix it...not the problem...so now Im on to the next on the list.

Any suggestions? My best bet is the EGR valve needs a good cleaning now. Anything else higher on the list than this?

 

From what I've seen and read, the passages do get dirty along with the EGR itself.

I would take off the EGR using some cleaner on it and the bottom passages to see if it helps.

 

So I read online about someone else that had similar symptoms with a honda civic....and it was with the O2 sensor that I replaced already; so to see if the surging was a result, just unplug it and see if the surging continues...so I unplugged it and BAMO surging gone! Turns out that the $45 O2 Bosch that says that it is compatible is not so much. I just ordered a Denso that was 65% off for $120. Looks promising though.

 

Crappy replacement parts is the second case of the car problems after design/assembly defects!
This why I am telling "OEM or .. junk yard parts only"!

 

Posted this in a random thread somewhere on accident:

I had this issue and tried a bunch of things. I did valve adjustment at the same time as replacing the ignition coil pack and that seemed to do it.

I had previously replaced the spark plugs, cleaned 02 sensor, replace map sensor. The spark plug replacement seemed to alleviate the issue but only for a few days.

You might have just 1 or 2 bad coils which you can swap around and try new ones to identify them but I just replaced all 4 to be safe.

Lastly I had this issue for the better part of a year before the car ever threw and engine code. Forget the code but it was a misfire code and told me the cylinder.

Ymmv but maybe something to check if you have exhausted other options.