Howdy all...one of the rare occasioms I get to come back to the board. The title sums up the problem. I tried several searches to no avail. I thought I remembered someone else having this problem last year sometime but can't remember the fix.

Thanks!

 

any vacuum hoses get knocked off by accident maybe??

 

No vacuum hoses disconnected that I can see...I just checked for the third time.

 

How high is too high and was the intake really dirty? Maybe you cleaned it too well allowing more air to flow through causing it to idle higher. I know when my bro cleaned out the throttlebody on his 3.0 the idle speed was a little higher. It was due for a cleaning though.

 

Alternate question...How do I adjust the idle?

 

There's a big screw on top of the throttlebody that you adjust w/ a flat tip screwdriver.

 

What RPM is it idling at?
Should be right around 700-750.

.....higher is usually a vacuum leak.

 

Idle RPM is around 1500 cold and 1200 warm. I'll try the idle adjustment screw. I'll also pull the intake hose off again to see if maybe some dirt is wedging the butterfly open.

 

Mine jumped up to 1200 or so after cleaning it out too. The idle adjustment is a large screw built into the intake manifold. When you stand looking into the engine compartment on the front of the intake manifold is a large screw. Clockwise to lower the idle anti-clockwise to raise it.

 

Not to state the obvious, but I'd try pulling the EFI fuse and waiting for a bit before tweaking the idle. I wonder if the engine just needs to re-learn settings with the improved air flow?

 

I disconnected the battery when I cleaned the throttle body. I replaced the alternator at the same time. I wonder if the idle bypass tube gets clogged with oil & gunk over time. Which may have been compensated for by a mechanic or two over the years by opening up the idle adjustment. After I cleaned the throttle body, I had plenty of cleaner left, so I removed the blow-by tube from the valve cover and sprayed cleaner directly into the intake while the engine was idling/ revved. It could have cleaned the gunk out of the idle air by-pass. Anyway, I adjusted the idle and it seems fine now.

But now that I've swapped out the oil, I hear a knock that I don't like and the radiator seem to be mysteriously low on coolant. I'm hoping it's not a headgasket leak and a loose rod.

 

I don't change the idle on any vehicles because it gives me a hint that something else is wrong. If my truck idles too low it usually means (plugs, TB cleaning, IAC cleaning, air filter, etc). When I do the maintenance the idle bounces right back where it should be until the maintenance is needed again.

...in your case someone may have adjusted it so that hint is gone.
When you finally get tuned perfectly, mark the screw so you know if anyone moved it.