900rpm idle

[ParanoidSVT]

Morning guys, hope your day is starting off Better than mine

Last August I had an extremely high idle at 1500 rpm. I started a thread here, they recommended changing the TPS sensor, and it not only fixed my idle but also fixed a transmission shifting issue I had months prior to the idle

Today I went and fired the truck up and noticed 1500 rpm…. I waited about 3 mins and it was idling around 1000..

By the time I get to the main road it’s already warmed up and should be at 750ish but it won’t go below 900

Instead of jumping on the highway I turn back around and came home

Sure enough it wouldn’t go below 900 and when I put it in park it’s back to 1000. Or right below it

I did some searching this morning and I guess my next step is vacuum leak or IAC valve

My question is, is there a diagram that shows all the vacuum lines for me to check?

I’m looking at getting a smoke machine on Amazon right now, see if that makes it easier to find the leak

Also while searching someone recommended changing the TPS, IAC and PCV valve at the same time

Considering I replaced the TPS (motor craft) I’m wondering if I should replace the PCV as well

Any advice is greatly appreciated

Thank you!

 

[ParanoidSVT]

Also wondering if someone can tell me where the PVC is located?

 

[Curious Hound]

From the factory, there was a vacuum diagram on a sticker on the radiator core support or maybe front edge of the underside of the hood. If it’s gone, you should be able to Google it if nobody posts a picture for you here.

The PCV is on top of one of the valve covers. On my 93, it’s on driver side toward the rear end of the valve cover.

 

[ParanoidSVT]

From the factory, there was a vacuum diagram on a sticker on the radiator core support or maybe front edge of the underside of the hood. If it’s gone, you should be able to Google it if nobody posts a picture for you here.

The PCV is on top of one of the valve covers. On my 93, it’s on driver side toward the rear end of the valve cover.

Thanks for the reply, do you believe I found it right after I posted… I fell like a jerk lol

I’m going to have to check, I don’t believe my sticker is still there..

 

[ParanoidSVT]

I also saw a video on YouTube where the guy was experiencing the same exact thing as me, and he cleaned the MAF, throttle body, and IAC valve.

And it worked for him

On the valve it says not to clean it, truck has 138k on it, factory IAC i believe, so I think replacing it with a new motor craft isn’t a bad idea

 

[ParanoidSVT]

Ok so alittle update, when I ordered parts yesterday, the woman came up with 4 PCV valves for the truck, so she ordered me all 4 and told me to take out my PCV and bring it in to match

I came home today from job 1, and figured I have a hour between having to go to job 2 let’s get It out

First I’ve never seen a PCV with an electrical plug, this is an electronic PCV?!

And two, I had to YouTube how to get the thing out, never would I have guessed you had to unscrew it..

Thanks to a guy on YouTube it made my life easier

I wanted to inspect that big rubber elbow that goes between the plenum and the PCV, I had no idea there was a long plastic tube inside there, it was COVERED in oil! And I mean covered!!

The PCV in the photo is when I cleaned the lower part, I don’t think this thing is working at all if there was that much oil in the upper plenum

And I mean oil was RUNNING off this thing.

I have to pick up the

MAF cleaner
IAC valve
And PCV valve

Tomorrow, I’m going to take and clean the throttle body too

I have seen on YouTube the blade is coated in Teflon? And that it’s recommended not to use any cleaning product on it besides soap and water

Is there any truth to that?

I also saw someone fix their 1000rpm idle by changing their coolant temp sensor..

Could that be true? The CTS is thinking the engine is still cold and keeping it reving high? First I’ve ever heard of that, but to a novice like me sounds believable

Thanks for your time, I hope this thread helps someone in the future, I’ll report back with my findings after the parts swap

 

[bills4065]

Your pcv valve should rattle if you give it a shake.If it does not- it is definitely no good.

 

[ParanoidSVT]

Your pcv valve should rattle if you give it a shake.If it does not- it is definitely no good.

Oh yes, my original rattles away! Lol I think I’m going to install the new one anyway, don’t think it will hurt

Hoping it’s the IAC… I want to tackle it tomorrow but I’m working a double, so I’m going to have to wait til Wednesday

Any advice on cleaning the throttle body?

thanks for your response! I appreciate it

 

[pjtoledo]

special coating on throttle bodies. use "throttle body" cleaners, nothing harsh.
the wires on the PCV are to heat it and prevent that oil from gelling.