Oscillating idle

[cwo4vr55]

After my 92 Laser has warmed up the idle speed seems to fluctuate between 400 and 900 rpm. It does not run rough when accelerating only at idle. I changed plugs and plug wires. Hope someone can give this beginner some tips, I have the Haynes Repair manual just want to go in the right direction


Bob

 

[flytalon93]

Test the ISC motor if it is operating properly. It is one of the most common problems with idle surge. To test check vfaq.com, they have a step by step procedure to accomplish it.
Hope that helps,
Steve

 

[eclipsegs-t92]

Have you modified your MAS?

 

[cwo4vr55]

I have not yet made any changes to the MAS I have only installed a K&N cold air kit and the car was idling rough before then. I not check timing yet. I am planning on installing a Stage 1 G-Box which gets spliced into wires 4 and 6 of the connector for the MAS/IAT. Hope you help me out here bro

Bob

 

[bdropped]

I am haveing a similar problem but my idle ranges from 500 to 2000. it doesnt surge all of the time some times it will hold a steady rpm. i start the car and the idle is 2000 it might stay that way all day or it might change when it drops past 700 it tries to stall. i have checked for vacu. leaks but nothing. i am running out of ideas. oh and about 4 gallons of fuel that is in my tank is about 8 months old.

 

[eclipsegs-t92]

block off your EGR valve, and clean out your throttle body really good. that should do it.

 

[cwo4vr55]

I will give that try tomorrow after back with you. I his fixes the problem will I need to get a EGV or?

 

[bdropped]

On myine i have the egr blocked but i found that i need a new ISC.