Sorry for duplicate post, posted in another forum with no response.


I've got an 89 C-350 with 460/e4od I'm having a couple problems with.

I just picked up the truck, so don't have a real history on it.

But the truck does not seem to have a fast idle when cold.
And after warming up has a rough idle. Revs good.

I pulled codes for KOEO in all I got was a 93
For CM I got a 33 and a 41

Any ideas would help alot
I tried A new ECT sensor. ( not installed but plugged in) No help
I disconnect IAC and the truck dies. Though the Iac seems to be original. Has a sticker that shows 10/88 build. Tested 9.5 ohms.