My Idle wont go down fast enough after reving a bit

[spitfiresk0690]

The car: 1995 N/T 5 speed...

I rebuilt my head and I put everything back together. When I started it for the first time the idle went way up for no reason at like 4 grand... the ISC needed to be cleaned... okay problem fixed... start in back up and clean idle but whenever I give it some gas or shift gears the engine speed tends not to go down very fast at all... I.E. your in first gear and you shift at 3500 rpms and by the time your releasing the clutch to go in 2nd gear the rpms have only dropped to 3000 rpms if that... what is it now?

 

[dr1665]

what is it now?

Vac leak somewhere. Just a slight one. Or, it could be that the o-ring on the IAC has dried out. Could be a misaligned throttle plate. It's nothing too severe, or the engine would rev to infinity and beyond, but there is definitely air getting into the manifold from somewhere when the throttle plate is closed.

 

[95 'clipse RS]

same exact problem here, replaced the head and did a tranny swap. and mine is also at like 3000rpm. is it right after you started it for the first time?? ive been trying to determine if this is because the fuel curve is not yet set telling the ecu to suck more air in. my car is running extremely rich and haven't been able to drive it yet to see if it is because of the ECU being reset due to a tranny mount i need to drive it. i can hear vaccum very loud, coming right from the intake filter so im thinking this is what my problem is, im also thinking that this is why im running so rich at idle. it also has somewhat of a misfire at idle, and the timing is near perfect, its off like a half of a millimeter.

does anyone know if this is the result of a reset ECU?? there is no hesitation throughout the rpm's, just a misfire at idle. it idles at 900-1100rpm.

thanx

 

[selmerguy]

i've never had this problem after a head job. i've done 4 of them myself and never had that problem. check for vacuum leaks also make sure the throttle cable is adjusted right. take off the intake pipe and look at the throttle plate.

 

[95 'clipse RS]

i just went and checked the throttle plate and throttle cable, and all is fine. any more ideas??

 

[95 'clipse RS]

ok, i got all my motor mounts in today, reset the ECU again, and drove it around for about a half an hour and everything started working fine. still has a tiny misfire but other than that it is running strong. im so glad to have my car back after 5 months. maybe your ECU needs to relearn the fuel curves and the other stuff it monitors. so just drive it around for a liitle while, but definately check the timing before you do so... i hope it straightens out for you the way it did for me.

peace

thanx dsmtuners and everyone for the help ive needed