W.T.K.: Honda Civic idling problems

[SRASC]

My friend went to check out a Honda Civic EXi (recently (2008) converted to manual).
He says though that if you rev the engine & then stop the RPM goes to about 300 & sounds like it will stall & then catches itself. While trying to balance the clutch it stalls.
One of my friends thinks that its 3" exhaust system may be a cause, where some think the idle may be set up wrong or if the idle air control valve maybe dirty & if thats the case how much will it cost to clean or replace it.
What do you guys think?

Thanks

[reiXmann]

Exhaust wont cause that AFAIK. What does it idle at? Check the idle screw and turn it up a bit (left to increase idle,right to decrease)...if that doesnt work,then you gotta clean the iacv

[xxxxsatoxxxx]

could check tps............

[reiXmann]

yeah,forgot to mention that ^

[SRASC]

It idles at 650-700. He's wondering if it could be idling low cause of another problem with the car?

[halfdef]

tps voltage should be between 0.450 - 0.500

[SRASC]

any other opinions?

[red_dragon]

what engine in the car ?

[SRASC]

D15Z4

[bluesteel29]

[red_dragon]

tps,iac,timing.. or if he buy the car already

check the mechanic