idle jumping

[phaseoneracing]

ok so my problem is as follows. i have a 97 eclipse spyder gst . i put a new motor. well.. junkyard motor . car runs good no overheating or anythig. i let it run for about 2 hours the other day. but it runs great for about 10 minutes. after that the idle goes from 1000 to 1500 and the drops back down and just continues to do so . if i put it in any gear besides park it runs normal. but in park it just keeps jumping like i said. i have found no vaccuum leaks. i dont know what i should check first. ive been seeing a lot of different answers. i wonder if anyone has solved this yet. please help . thanks

 

[AdR]

Checked the idle valve?

 

[r1991_4g63t]

I'd definitely check this first

Checked the idle valve?

 

[r1991_4g63t]

I had the same problem with my old 1g, ran normal after unplugging it til I got it replaced

 

[phaseoneracing]

havent checked yet. will do tomorrow. idle air control valve correct? if i just unplug it i wil be able to tell if thats the problem?

 

[r1991_4g63t]

Yes thats correct. Doesn't always work that way. But when I got my car it was unplugged, plugged it in and idle started jumping, unplugged it again til I bought a new one. But that was also a 1g

 

[J_Hock]

You can eliminate the idle control valve by doing a simple resistance test at the plug. I remember there being a video on YouTube that shows exactly what pins are the coil.

If that tests good I'd say that you're looking for a boost or vacuum leak.

 

[r1991_4g63t]

You can eliminate the idle control valve by doing a simple resistance test at the plug. I remember there being a video on YouTube that shows exactly what pins are the coil.

If that tests good I'd say that you're looking for a boost or vacuum leak.

Boost or vac leak wouldn't go away by putting it in gear

 

[phaseoneracing]

just started it today. unplugged the idle control valve. still jumped up and down. few minutes later saw a little coolant on the ground. checked into it and found lower heater core hose leaking. wondering if this could have anything to do with it. obviously i have to change that now but im just wondering if that might help the idle.

 

[r1991_4g63t]

That shouldn't have anything to do with the idle