I have a 93 civic 4dr w/ a 1.5 d15b7 manual tranny and just recently it started acting up. what its doing is jumping up and down from 1.5 to 2.5 rpm constanly. I took the short ram ai off and cleaned throttle plate and intake tubbing and it diddnt help. so if anyone has any other suggestions please let me know.

 

i have the same problem with my 2001 civic ex...its usually after the cars been sitting for a while (like a few hours at work) and then i will start the car up and drive to the stoplight and when i stop at the redlight the idle jumps up/down just like you said from 1500 to 2500 rpm...i would love to know what is causing this!!! if anyone has an idea please post up on here it will be GREATLY appreciated!!!!

 

It might be your vacuum hose... Check to see if they are all connected and for holes and stuff...

 

i check all hose and none are bad and i spraid carb cleaner all around intake and the throttle didnt jump

 

You're a pro man! Sorry my advice didn't help...

 

It can be also fast idle valve or a lack of coolant...

 

You can also take off the Idle Air Control Valve and soak it in some carb cleaner and wash out the carbon and dirt. Also replace your fuel filter if you haven't in the last 15000km, this will also give you a good boost in fuel economy and improve throttle response. Put some fuel treatment in the tank like seafoam.

 

Run SeaFoam through the engine as well. Someone tried it recently and said it really worked well.