I've read several of these forums on idle surges in hondas and none of anyones fixes worked for me.. i dont know what to do next. IACV wasnt the problem, i have unplugged every sensor on the tbi one by one looking for idle changes. which every sensor causes its own idle issue so i assume they are working. no air in coolant system. cant find any vacuum leaks...

 

Chec engine light on?

 

What do your fuel trims look like at idle and under load?

 

If its on startup or when its cold out, check your FITV. It can cause some funky bouncing idle issues.

:edit: im not sure if the y7 even has a FITV may have stopped with the z6

 

No fitv on y7

 

Throttle body gaskets go on those D16Y7s and can be difficult to pinpoint. I had one that surged very badly, emptied a whole can of TB cleaner on the thing and never go it to stumble. Long story short replaced the TB gasket and fixed the issue.

This is just my anecdote. I am not for throwing parts and time at a car without a diagnosis.

 

OBDIIs idle unevenly for several minutes the first start after the ECU has been reset by losing power. Make sure your back up fuse circuit is OK, or the ECU will reset every time you turn the key off.

Take the air filter box off and try blocking the holes in the side of the throttle body before the throttle plate. You should be able to stall the engine out by blocking them. If it doesn't quit with all the holes blocked, there is an air leak.

Also I would ohm test the ECT coolant temperature sensor. If the ECT tells the ECU that the engine is cold it will idle fast. If the ECT is giving inconsistent readings, it will idle inconsistently.

 

I had this on my 2000 Honda Accord. It was the throttle positioning sensor or TPS. The dealer wants to sell you the whole throttle body because there are no screws to take off the sensor. A quick Google search will tell you that the part is $30 and you make slot cuts into the screws to get it off with a Dremel tool. It takes about 30 minutes and go buy the aftermarket parts at an auto parts store.