my car has had this weird idle for a few days now. not sure to what it could be.

it revs -/+ 500 rpms when it's idle.

it's weird. if i rev it 'till about 4 or something then gently bring it down, it will usually go away until i rev it hard / start going somewhere. then when i idle again, it's back. it's been cold and warm latly, and it never seemed to matter.

my lights dim out a little bit too. but my car has always done that. (figured it was the underdrive pulleys or something.

thanks in advance for the advice.

 

so it is idling at 500 + or - or it is fluctuating 500 up and down? If it is fluctuating it could be a number of things...I know its tough to check for but see if you have a vacuum leak, Ive also heard of it being things such as a dirty IACV but in those cases it tended to stay more consistent in that it was constantly staying too high. Could be a vacuum leak and the IACV is compensating by raising it, then the leak lowers it, and so on.... or another thing to check out is the fast idle thermo valve which is located on the left side of the throttle body on the bottom kind of, it has phillip screws and is a beyotch to get to but it could be the problem if its dirty.... Also, try and pinpoint an exact occurance of this, does it only happen when you use power such as headlights, a/c , fan switching on? or is it all the time?

 

it varies +/- 500 (usually ranges from 800-1300)

i'll look at it when i have a day off. do you think i'm loosing any power?

the lights have always dimmed, no matter what the conditions. and it doesnt matter if the car has the a/c on, windows inuse, lights on, etc, it acts the same.

 

how many miles on your car? if you have 70K+ then it could definitely be a dirty IACV or fast idle thermo valve because a quirk about hondas is that they get carbon build up on those parts once the mileage starts getting up there... either that or sounds like a vacuum leak... hopefully its one of those things cause if it is power related then it could be a number or things.....

 

alrighty..thanks for all your help. :thumbup:

 

sorry , I know it probably didnt help as much and those were probably obvious insights, but sometimes its the simplest things when it comes to annoying quirks like that, so might as well check out the simple/cheap stuff before you get hosed for 300bucks....

 

if it was a vaccuum leak, the idle would go up, down, up, down, up, down, etc. If the idle just drops low when u stop, check the distributor and the MAF. I had the same problem for a while. It would drop to about 500 and shake like it was gonna stall. weird. check all the obvious, spark plugs, wires, cap, rotor. and def. check the distributor for oil. that very well could be the problem.

 

also get a can of throttle body cleaner and clean it good. mine was filthy, sooo much black smoke came out the exhaust. i did it till the smoke wasnt black anymore, that def. helped a bit.

 

then it's a vaccume leak.

 

got it fixed. some hose was just loose. for some reason it fixed when i put it back on tight.

thanks for all the help.

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