89 C4 High Idle
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The idle speed is controlled by the ECM with the IAC. The ECM can lose control if there is a vacuum leak.
I don't understand the TPS of -0.3. What does that mean? What are the units? Usually TPS is expressed in percent. Is that -0.3%?
I don't understand the TPS of -0.3. What does that mean? What are the units? Usually TPS is expressed in percent. Is that -0.3%?
Thread Starter
Heel & Toe
Joined: Sep 2015
Posts: 19
Likes: 0
That was it! I have not ran it down yet, but I went and got myself a gage and confirmed it. I haven't found where it is yet but tried with starter fluid.
It's running as expected this am after looking for the leak. Weird but ok. I hate trying to run down this type of intermittent issue.
Thanks Again!
It's running as expected this am after looking for the leak. Weird but ok. I hate trying to run down this type of intermittent issue.
Thanks Again!
Thread Starter
Heel & Toe
Joined: Sep 2015
Posts: 19
Likes: 0
I don't know? It seems to be running much better this AM. I'm sure I have a vacuum leak but have not located it yet. Maybe the TPS was over compensating for the leak and trying to correct the idle speed. My un-educated guess tho...
Instructor
Joined: Oct 2014
Posts: 162
Likes: 1
From: Steinbach
Mine had a high idle and it was the throttle body , loose shaft one one end. It was only noticeable after it warmed up. Try holding or moving the throttle body where the linkage is when it's at idle.
