91 300e idle surge
 

I changed the idle control valve, it idles at 1500 rpm. The short hose was replaced, but I was not able to replace the long hose connected to the intake. The long hose is broken, and it was taped with black tape. Prior to the new idle control valve replacement, I cleaned the old valve with carb cleaner. It worked for a week, then it idle to about 1500 rpm.

Is the broken hose (air leak) caused the problem, or something elso.

Jack

The engine will suck in as much air as it can get, and the EHA will try to compensate with fuel when the O2 sensor says you're leaning out, even if the AFM doesn't see the air leak. So, yes, you have an air leak. Replace the hose, and any others that have dried out in the idle circuit, and the lower AFM plenum as well would not hurt.

Steve

Jack, were you able to fix it?

I have the idle surge problem with my 300TE.

It fixed
 

My problem was throttle linkage, I spray some WD40 to all the linkages. The surge was gone.

I have changed both the idle control valve and hoses, but it did not work.

Jack

Throttle linkage????? That one isn't even on my list. Seems like there's about a dozen categories of failures that can cause an idle surge.

Good to hear that yours is fixed, thanks for the reply!