my idle problem started when I got the motor put in. Then it went away. Never knew what the problem was.

I since then installed cams and had it tuned with hondata. Car ran fine then my plans changed. Recently had cams taken out stock cams and stock ecu put back in idle problem is back...nothing has changed.

ENGINE:
98 JDM type R (stock)

PROBLEMS:
1. The engine will idle at 3k when cold. Its goes down to 2.5k when warmed up for about 5 minutes. If i shut it off and restart it when its warm the engine will idle at 1.5k. If I let it warm up until the fan kicks in then the car will idle at 1k. weird...

2. When I drive and come to a red light or start to slow down to stop, I put the car in neutral and apply brakes to slow down. Only issue is the Idle will surge to 3k. it will stay that way until I come to a complete stop. Once the car stops completley the idle goes down to 1.5k and stays that way. The only way I can get it to go back to idle at 1k is to shut the car off and start it again. This is really starting to eat away at my gas. Every time I go to stop the car surges to 3k.

What I did to try to fix:
1. adjust Idle
(unplugged the IAC and adjusted to spec plugged in and reset the ecu)

2. checked for vaccum leaks

3. cleaned IAC with brake clean
(it was working...when I unplugged to fix idle it did what it was suppose to..motor bogged check engine came on.)

4. switched out to another known good type R ecu.....didn't fix it.

Any help would greatly be appreciated, its killing me on gas.

 

I have almost the EXACT same issue on my ITR swap. Mine likes to jump up to about 3K rpms after you get going past like 5mph...and holds at about 3K rpms until a COMPLETE stop. Very VERY annoying.

X10000000 for incite to this issue!

 

same here!

 

I can think of a couple things.

1. Check to make sure that the MAP and TPS plugs are not switched. They are identical and this is easy to do.

2. Check and clean your MAP sensor.

3. Double check for vacuum leaks. This sounds like the most likely cause of your problems. Use starter fluid, spray small bursts around the intake manifold flange and throttlebody/IM flange. Any leaks will cause a surge in idle.

 

i had this same issue for the last 7 months, and finally got to fix it.
since you have done all the idle throuble shoots.

try replacing the thermostat, and also maybe change the primary O2 Sensor.

Thermostat - it is crusial to have normal working temp, if you temperature is lower than normal this will make you idle high.

O2 - Believe it or not, this will bring back your mpg and also the slight idle issues.

I replaced these two and after 7 months of head aches, finally got it working.