bouncing rpm's

[crashtestracer]

ok so I just bought a 98 gsr great lookin car runs reall well except for 1 thing. The rpms randomly bounce from about 2.5k to idle of 1k. I had this issue a long time ago when I had a 88 CRX si and I took it to several mechanics no one could ever tell me what it was. Does any one here know what could cause this? dirty MAP sensor maybe?

 

[red98teg]

honestly im no expert here... but i had a wandering idle but it didnt really jump that far... might go from about 400-800 rpm. i solved it by doing a 3 part cleaning system(fuel injector cleaner, throttle body cleaner, and intake cleaner(same stuff as seaform cleaner)) and changing my fuel filter. also plugs and wires might be a good investment.

 

[jdmbozhko]

i had a chipped p28 and my rpms jumped too i took it to my acura guy and he adjusted a few things and regulated a few things but the main problem i had was my ecu i changed it and i had a perfect idle car runs like a champ now.

 

[crashtestracer]

i was told that it could be the idle control valve. I am also having a sound from what I think is the trans that sounds almost like a grinding sound happens whenever the engine revs up. would this be throw out (aka release bearing) or the pilot bearing?

 

[GSROWNSU]

check your iacv (intake air control valve) may need to be taken apart and cleaned. Had a gsr with a funny idle and cleaned up the iacv as well as tested the unit and problem was fixed.

 

[crashtestracer]

which one is the iacv? and does anyone have any idea what the sound is?

 

[jdmbozhko]

on the back of the manifold....cylinder black piece

 

[crashtestracer]

thanks I'll take a look at that tomorrow

 

[omgherb]

i had that problem and i sloved it by changing the dizzy my old boss who use2 run a honda shop said its the igniter that goes bad and cause it to do that most of the time it happens from some1 installing a tachometer and the line isnt secure correct or a incorrect amount of amp anyway change your dizzy and you should be good

 

[dc2b18]

are you sure it isn't just warming up?

 

[crashtestracer]

it does it when it is warm and cold. the tach is stock. sorry to add to this but the guy i bought it from also said he has a type R intake mani on it is this possible? I am lookin to get a short ram and want to make sure it will fit the first time

 

[Driftnasty]

I had the same problem on a 94 gsr- Took my mechanic forever, but by accident he finally figured it out. Seems like this might be your problem.
Your TPS( on the firewall side of your throttle body) has a thermostat inside of it, when the car changes idle or warms up, that thermostat flips. Mine had carbon/dirt built up inside of it and everytime the stat tried to flip it hit the carbon, and the result was that the idle went up and down constantly. He cleaned it out and it ran perfect after that. But then I blew the engine lol.
Hope this helps.

 

[Red Raptor]

is this problem just a wondering tach or is the engine actually reving up and down?; mine is just the tach showing the wrong rpm jumping all over the place but the engine is at same speed.

 

[blaketeg]

vacuum leak?