My TBI 350 in my 90 blazer was running at about a 1000 rpms with no load so I changed out the IACV now it idled anywhere from about 700 rpms to 1500 rpms and now I'm scratching my head what to try next. Any help would great!
CK5
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Erratic idle
- Thread starter de3en16
- Start date
CherryK5
1/2 ton status
Pretty sure they run around 1500 until they warm up. I think. I know my moms 6.0 does that.
shaun89
1/2 ton status
nvm,i should go to bed,i didnt fully read ur post how u changed ur IAC already
BIG UG
Registered Member
Tps check it out
First thing to do, is to check/set the base idle. The IAC can only add air, it can't take any away.
So there is a procedure to set an idle speed without the IAC in the mix so that it has what it needs to work with.
There is a thread or two here on how to do it. Someone should chime in with a link. I don't remember where I last saw it.
Its a basic setting that needs to be right before you start doing anything else.
If that does not help, then you have at least eliminated one variable.
So there is a procedure to set an idle speed without the IAC in the mix so that it has what it needs to work with.
There is a thread or two here on how to do it. Someone should chime in with a link. I don't remember where I last saw it.
Its a basic setting that needs to be right before you start doing anything else.
If that does not help, then you have at least eliminated one variable.
I thought about that to but some times it idles right where it should about 700 rpms then I drive it a bit then it idles high drive it some more and its back down again but I'll check into the base idle like you suggested maybe its a loose screw in there
The most common cause, by far, is a vacuum leak.
You can find out if it is by adding fuel to the air around the engine.
Lots of people spray starter fluid around, but I don't like that.
WD40 works too, but leaves everything greasy.
Carb cleaner works I'm told.
Personally, I like a propane torch, unlit. Just turn the gas on, gently, and move it around all the hoses and gaskets.
If you put it next to a vacuum leak, the engine will speed up.
You can find out if it is by adding fuel to the air around the engine.
Lots of people spray starter fluid around, but I don't like that.
WD40 works too, but leaves everything greasy.
Carb cleaner works I'm told.
Personally, I like a propane torch, unlit. Just turn the gas on, gently, and move it around all the hoses and gaskets.
If you put it next to a vacuum leak, the engine will speed up.
A leaking EGR will cause an erratic idle also. just a thought.
update
I changed out the EGR and used carb cleaner to check for a vacuum leak. The nuts on the EGR where way loose. I un hooked the batt to reset everything and started it up checked for vacuum leaks and nothing. So I took it for a test drive and now it stumbles if you give it a little gas but after the it pulls hard like it should. I got it home and it idles right at 500 rpms in gear and 750 in park.
I changed out the EGR and used carb cleaner to check for a vacuum leak. The nuts on the EGR where way loose. I un hooked the batt to reset everything and started it up checked for vacuum leaks and nothing. So I took it for a test drive and now it stumbles if you give it a little gas but after the it pulls hard like it should. I got it home and it idles right at 500 rpms in gear and 750 in park.
update
I changed out the EGR and used carb cleaner to check for a vacuum leak. The nuts on the EGR where way loose. I un hooked the batt to reset everything and started it up checked for vacuum leaks and nothing. So I took it for a test drive and now it stumbles if you give it a little gas but after the it pulls hard like it should. I got it home and it idles right at 500 rpms in gear and 750 in park.
I changed out the EGR and used carb cleaner to check for a vacuum leak. The nuts on the EGR where way loose. I un hooked the batt to reset everything and started it up checked for vacuum leaks and nothing. So I took it for a test drive and now it stumbles if you give it a little gas but after the it pulls hard like it should. I got it home and it idles right at 500 rpms in gear and 750 in park.
