Car reving by itself.....

My 93 Prelude Si revs by its self sometimes, generally in cold weather and revs between 1000 and 2000 RPM's. I installed a Iceman Intake a few months back and i dont think it has done it since. One thing that it still does is it revs when shifting. It revs about 600 RPM's when i hit the clutch. It has done that since i got it used 2 years ago. Another problem I have had for a while is rattling coming from my heads. I have had my valve lash adjusted twice and nothing has changed. It is a loud mechanical noise and its seems to emitt from the right area of the head but it is hard to tell. It rattles alot right around 2500-3000 rpm's but after the car warms up and idles lower it calms down. My friend is a honda mechanic and is not sure but someone told him that i need to retorque the heads to get rid of the noise. It has gotten worse in the last year or so. If i cant fix it i may rebuild my engine because it has 135,000 miles on it. THANKS for any info guys...

i have the same problem with my 95 vtec. i bypassed the throttle body coolant line and ran it back into the block so i figured it was because the air was too cold going into it. i never have the problem in warmer weather and since i live in ft. lauderdale i dont worry about it too much because we only have a week or two of really cold weather a year.

try resetting the ecu. i just reset mine and the reving stopped. but its also in the 60's today

does it stop once the engine warms up? our accord does that sometimes when it is cold but stops once it is warm. or it may be a vacuum line .

mine would stay going even once it had warmed up

Originally posted by 95vteclude
mine would stay going even once it had warmed up weird. we had been working on the accord, replaced the head gasket and Drift took out some "un-needed" vacuum lines. thats why ours was reving like that so he took one small hose and closed up the open vacuums. now it does it sometimes while its in idle but only when i dont let it properly warm up before driving. takes about 2 minutes before it stops.

the wierd thing with mine is that there wasnt any problem when i first started the car... i'd let it warm up a minute or two and it wouldnt rev at all. but once i drove it and got to a stop light about a half mile down the road is when it would start to rev. i have all the vacuum lines secure and/or closed up so i dont think its that. could it be from having a breather on the on the valve cover? i took a pic

YOUR PROBLEM TO ME SOUNDS LIKE IT IS WHAT US AUSSIES CALL HUNTING. THIS IS WHEN YOUR MAP SENSES A LITTLE MORE ENTERING AT LOWER REVS OTHER THAN THE AIR ENTERING THROUGH THE FACTORY SET THROTTLE BODY. IF IT IS JUST A VACUUM LEAK SOMEWHERE START WITH BLOCKING EACH HOSE INDIVIDUALY AND SEE IF THIS FINDS THE LEAK OTHERWISE SIMPLY ADJUST THE THROTTLE POSITION SENSOR UNTIL THE HUNTING FINISHES. 93VTEC SUPERCHARGED LUDE (MD)

THanks guys, have any idea about the crazy sound my engine is making.... See first post for details......

I think it's just idiling high because it's cold outside.:D

it should idle higher is cold weather. but if it jumps up and down you've most likley got a vacumm leak. i've got one after my engine warms up...its annoying as hell.