rpms rise than fall

[jbcpat]

wanted to see if any one could help me. i have 91 accord it runs great but after warming up. i will sit at idle and the rpms will go up to 2,500 and then fall to the norm than do it again,but it doesnt happen all the time..... so there it is some one help me!!!

[badmanferg]

possible vacc leak, check pcv valve also....any cels?

[h22sparkle]

Check for leaks begin to pinch hoses at first if you arent shooting off any cells or it can be bubbles in the coolant.

[blackedout]

Same thing happened to my stock F22.. it was the high idle valve? or something like that.. You can adjust it by the screw on the side of the Throttle body.. My buddy said the same thing happened on his H22 and he had to buy a new one about $300. Hope this helps..

[Ilikebigbutts]

its probably a vaccum leak, check all the vacc lines that go to your throttle body and evap control box.

ILBB

[jbcpat]

im not the best car person so i dont know what a pcv valve is ,but it's not shooting any cells,could it have anything to do with my intake, but like i said im no car man so any help or pictures of what i need to check or do would be appreciated......

[h22sparkle]

start pinching hoses on the intake manifold 1 by one when the idle stops and you have your hose pinched up thats your problem right there. I went to a car meet with my shit goin off like that i found it out when i went home

[93accordexcoupe]

haha yea i remember that, it was like VVVROOOOM vrrrooom VVVRROOOOmm vrrrrroom

i had to convince u to come cause u were like no my car sucks it idles funny, then u got there and everyone was like thats a car

yea now its happening to me with my idle

where exactly is the idle screw on the side of the TB?

[ehulst]

DANGER: HIGHLY EXPLOSIVE GAS: I AM NOT RESPONSIBLE: DO AT OWN RISKget a little bottle of propain and put a rubber hose on the end of it long enough so the bottle is far enough away from the manifold( 8 inches of rubber hose should do it) do short litle burst of to all vac hoses and around the base of the manifold gaskets....i mean short burst as in open then close open then close dont keep it open longer then 1 sec( even thats too long)..if u notice a rise in RPM and a steady idle thats where your leak is.....another thing to check is your FIV, its the tall wide peice on your manifold that has 2 coolant lines running up into it, not the one with the electrical line going too it the one next too it on the right...my h23 had been doing the idle problem for weeks till i took that off and adjusted it now she normal sitting @ 720RPM and doesn't bounce or do erractic idleing...

http://www.cb7tuner.com/vbb/showthread.php?t=12106

[Raceboy]

it's most likely your engine's fast idle valve located on the bottom of your throttle body theres a coolant hose that runs to it. it's a fast idle valve when the engine warms up it slowly brings the idle down. and if it goes bad it makes your engine idle go up and down. mine's bad as we speak. i'm going to go hit up some junkyards to get another one.

[thompson324]

or you could have bad valve seals like myself, just took the head off my car and took it apart and they were shot, if the valve seals are leaking then the car will idle like yours, but mine had some smoke coming out the tailpipe especially while shifting so thats where i got my conclusion

[93accordexcoupe]

well i just fixed mine, throttle body gasket was bad. i got a new one and put tons of sealant on it, idles at 850 rpms now