What is the correct idle speed for a 4.3 Vortec with CPI? (1993 model)
Mine idles at 625-650 in park, 575-600 in gear. I think it is too low but not sure. Darn GM manual keeps mentioning "prefered idle speed", but never says what it is, unless I am overlooking it. I suspect my IAC may be on the blink.

Sounds about right.

Is there a way to ajust the Idle on my 1998 blazer, I think it Idle's a little too low, 500 in park--550 in gear, Should I be looking at IAC-TPS???

Is there a way to ajust the Idle on my 1998 blazer, I think it Idle's a little too low, 500 in park--550 in gear, Should I be looking at IAC-TPS???

No way to adjust idle, I would be looking at other things.

Tuneup is in order if you idle speed is that slow.

I have under 1,000 miles on the tune up I did in May 2005,
New AC Delco Plat plugs .060 gap
New AC Delco Cap
New AC Delco Rotor
New AC Delco fuel filter
New fram PCV Valve
New Fram Air filter
Cleaned MAF
Mobil 1 oil
No Codes Scanned.....
This Truck runs like a scared rabbit, just a little low on the Idle?

I'm Lost... :banghead:

Remove your IAC valve clean and scrub it with a toothbrush and TB cleaner.

Then scrub the housing it inserts into.

It will run rough when you first start it again but it will level out.

Thanks BlazerLT, I'll give it a shot.