Idles right cold but throws a check engine light warm and surges at idle warm???

[blacksambo]

Hi Group,
My wife's black 54K '99 starts the day out right, but she comes home with the light on, and the idle surges up and down when restarted warm after a 25 mile run home. (I just disconnect the battery and the light goes out.) Any suggestions greatly appreciated. Thank you all.

[AndyC]

Humm not sure if it could be the same problem I had this weekend. I just checked mine and I had trouble codes 171 & 174 stored. I reset them with my Scan gauge II and looked around. I had a vacuum leak coming from the left side of the common chamber - Intake manifold. Turns out I have a leak in the lower gasket Well I just used some gasket sealant on it and I'll check tomorrow to see if it sealed tight.

[circmand]

Have Napa autozone or other place read the code you do not have enough inof for us to help you

[WormGod]

I am betting it's a 171. Like I said in another thread, this is an epidemic going around. I call it the "171/174 VX Flu".

Do get the code run and see what you get though. This exact symptom has been popping up quite a bit so it should be able to be remedied pretty fast.

[don moore]

i had that last week..it freeked me out..i thought oh no .....not me...
so i shut it down ..checked and cleaned the pvc..air cleaner gas cap.checked all the wires and hoses.checked the oil and other fluids.and added some heat to the tank..let it sit for a while then put some premium in it and now its all gone ...wierd.runs like a top now..

[circmand]

but got a P1441. I beleive I saw a post for an FTP fix but search just keeps bringing up FTP as a computer site. Anyone know where that post is?

[blacksambo]

Thanks for the input. Problem persists and I will try to get the code.

[VXtreme]

Check the idle control valve on the throttle body. They tend to carbon up and if you remove it and clean it where it goes into the throttle body with a good MAF or other cleaner your problems will go away. You will have to remove the throttle body to do this.... a good idea anyway because this way you can clean the whole throttle body out with the cleaner. Been there......done that...... it should help greatly.

[WormGod]

Check the idle control valve on the throttle body. They tend to carbon up and if you remove it and clean it where it goes into the throttle body with a good MAF or other cleaner your problems will go away. You will have to remove the throttle body to do this.... a good idea anyway because this way you can clean the whole throttle body out with the cleaner. Been there......done that...... it should help greatly.

+1

You would not believe the build up you can get on this thing. As said, MAF cleaner and a soft cloth will do wonders. Not a bad idea to gently clean the valve's ports on the throttle body too, as those get just as carbonized.

[Gussie2000]

I always let the VX run no less then 5 minutes to warm up enough @ idle,if I don't then engine light says hi,especially if weather is pretty cold.
Beside that engine lacks power when i drives off with engine cold.
Once i read over the net that modern gasoline engines buildt from 1998 needs no warming time.....yeah right.
Even air fighters such as F-16 warms up before take off,how in the hell's name a regular engine shouldn't.
If this is the case escenario with you guys then you know what to do.

[blacksambo]

Well. I got the codes. You are right, 171 and 174. I heard some sucking/hissing and there was a vacuum hose amiss. That fixed some of it. Then I could still hear vacuum leaking around the driver's side plenum, just on the seam where it meets the throttle body. Gasket sealer did not stop it, nor did torqing it down more. So, I guess I'm stuck removing the plenum and puting on a new gasket. Right??? Is that tricky or a straight forward job? Thanks.

[WormGod]

Its not tricky and its straight forward, but a pain in the arse, IMO, haha. The only thing that might be a hassle is the fuel rail. It will either be with you or against you. Tends to be different for everyone. You may just be able to lift the manifold high enough to replace the gaskets without rail removal though. Unsure, I never tried.

After all the new parts, cleaning, and rebuilds I did in my VX, I am still left with a 174, which I can not for the life of me solve. Managed to get the 171 to go away for good. My starting idle is still somewhat boggy for about a minute but then it's solid and healthy. My hunt for the 174 continues, heh.

[blacksambo]

Thanks for the wisdom, it's a big help.