XSRCivic

iTrader: (19)

ok well the last week or so my car has been idleing funny.. I left off the gas and put it in neutral and begin to stop.. of course the rpms drop down to 800 or so.. you would expect it to rest there until I press the accelerator right? Nope.. it goes to 800..revs to 1800..drops.. revs.. drops..revs.. then finally after being stopped for about a minute it drops and stays at 800. I thought maybe my throttle might be sticking and was planning on checking that out tomorrow. Now on the way home something really wierd happened. Instead of the revs dropping to 800, it wouldnt drop past 1500 rpms and felt like it was pulsing kinda like a constant voom voom voom voom.. soud like it would be reving back and forth from 1500 to 1600, if that helps. So i get home, i turn the car off and start it up.. goes back to doing the 800 to 1800 idle thing on me.

Ok now things that are not stock are.. header, throttle body.. stock intake, well half stock half aftermarket.. still have the filter box on but a cold air pipe coming from it. I'm thinking its something to do with the throttle body. I dont know how a misfire would act in a 4 cyl car, i never owned one before. But if it was a misfire, it wouldnt just go away? Anybody got any information on this? thanks a million.

gearbox

iTrader: (95)

First what kind of tb are you running? Is it full aftermarket or bored out stock and where did you get it done? Erratic idle is usually a sign of a broken tps, which will require the purchase of a new one just to get the sensor. I know maxbore.com puts screws on the tps so it can be removed if needed. Normally there are just rivets tho that can't be taken off.

So the possible problems are bad tps, bad iat or other air sensor, throttle cable too tight, or even bad TB if it's too big. Now I know you prolly did this, but whenever you change the tb, you must reset the ecu and let the car relearn the idle by letting it sit on for 5 mins after warmup. Otherwise the idle will always drop out or stay high. My money is on the TB tho.

XSRCivic

iTrader: (19)

it is a bored throttle body.. i did let it sit when i first installed but it just recently started to do this when it gets cold.. i have the stock one i'm gonna out it back on and see what happens.

gearbox

iTrader: (95)

Try the ecu reset again to see if it does anything. My bored tb idled just like stock except the engine would bog all the time when accelerating from a stop. I think the air velocity just isn't fast enough.