Stumble at idle....ideas?

[dec322]

I was pulling into a parking space the other day and she died on me. I started it back up and parked and she died again.

Here is what I know: She runs fine until I come to a stop or when I start her up. Then she will start acting like she wants to die....the rpms will drop below 500 and the voltage drops below 14 (on the gauge). One thing that is weird is that the voltage on my yukon reads above 14 (usually about 15) which seems high to me...kinda like the alternator is acting up.

The truck has 102k on it and I changed the fuel filter and plugs a few thousand miles ago. Its been running fine up until last week after I got it back from the body shop....my wife hit something and I had to get a fender replaced.

Ideas?

 

[Rivieraracing]

Dirty throttle body!!!! Take your air intake tube off of your throttle body, buy some Seafoam Deep Creep and spray the crap out of the throttle body flapper as well as inside of the throttle body, wipe off as much crud you can! Follow the directions, it should solve your problem! Also pick up some MAF sensor spray and clean your Mass airflow sensor while you are at it, and make sure your air cleaner filter isn't too nasty or replace it while you are at it!

 

[BlueTahoe2001]

There is a Fuel/Idle air vacuum switch on these Tahoe's that seem to go bad. I just replaced mine that was doing the same, Let me dig up the part number for you.

 

[NoChrome]

If that dosent work you might have to do an idle relearn. if the battery was discoed for any length of time. let it idle in each gear, inculding P, R & N for not less than 5min.

 

[DarkTahoe00]

Mine did something like this when the battery went bad so I would start with that and alternator have the both tested!

 

[dec322]

Thanks for the input guys. I'll definitely get some seafoam and clean the TB and also clean the MAS.

I'm also interested in that fuel/idle switch. How much did that cost? Did you buy at a dealer or local parts store?


What does y'alls trucks voltage look like according to the stock gauge? Mine is above 14 which seems high (compared to other vehicles I've owned) so I'm wondering if its overcharging.

 

[NoChrome]

Most veichles keep a steady 14.4 V

 

[dropmech]

My idle is at just over 14 as well. I've had similar problems with two other vehicles in the past and Sea Foam helped out.

 

[dec322]

Alright guys. I bought some seafoam tonight and plan on spraying through the TB tomorrow.

One question: Do you guys use it anywhere else? I saw that you should spray it through the vacuum if the vehicle is port injected. Is our trucks port injected?

 

[BOSS]

Damn, look at all the help

BOSS is a PROUD ass member of TahoeYukonForum.com !!!!!


BOSS

 

[dec322]

Damn, look at all the help

BOSS is a PROUD ass member of TahoeYukonForum.com !!!!!


BOSS

?? I'm proud to have you. Now....answer my question.

 

[BOSS]

?? I'm proud to have you. Now....answer my question.

I'munna go with a bad alternator. Every other suggestion has been made


B

 

[Chads93GT]

Its definately a dirty throttle body. The idle air bypass is built into it, when it gets gummed up with carbon, you have the problem of dying at idle. Ive unbolted my throttle body twice and hosed it down with carb cleaner on the front and back. I also shove a rag into the intake to soak up any spray that gets in.

the only seafoam ive ever used was in the gas tank and once through a vacuum line in the intake. If you bought the seafoam in a can, you cant use that to clean the throttle body> just get some carb cleaner, remove the bolts holding the throttle body to the upper intake and pry it down. Leave the coolant lines connected. makes it more difficult to move, but its better than dumping coolant all over the place.

 

[dec322]

I'munna go with a bad alternator. Every other suggestion has been made


B

Yeah, I'm going to have it checked tomorrow. I figured the TB will need cleaning regardless seeing as I have a little over 100k and it has never been done. I'm just wondering if seafoam through the tb is enough do I do it in the vacuum too?

 

[Chads93GT]

You wont have enough vacuum to suck seafoam through the intake its self. I tried doing that before you have to manually remove the throttle body to spray it down.

 

[dec322]

Its definately a dirty throttle body. The idle air bypass is built into it, when it gets gummed up with carbon, you have the problem of dying at idle. Ive unbolted my throttle body twice and hosed it down with carb cleaner on the front and back. I also shove a rag into the intake to soak up any spray that gets in.

the only seafoam ive ever used was in the gas tank and once through a vacuum line in the intake. If you bought the seafoam in a can, you cant use that to clean the throttle body> just get some carb cleaner, remove the bolts holding the throttle body to the upper intake and pry it down. Leave the coolant lines connected. makes it more difficult to move, but its better than dumping coolant all over the place.

I bought the seafoam in a spray can. The direction tell me to spray it into the TB. It also says to open the TB and spray through the TB. I'll remove it and make sure it is nice and clean....all the way through. I won't worry about the directions to spray it into a vacuum line.

 

[NoChrome]

I bought the seafoam in a spray can. The direction tell me to spray it into the TB. It also says to open the TB and spray through the TB. I'll remove it and make sure it is nice and clean....all the way through. I won't worry about the directions to spray it into a vacuum line.

I may or may not know a guy, who put a 90* elbow on the intake turned it straight up poured in the seafoam and floored it... 8 beers, seafoam, and car keys make for a bad night.

Nothing bad happend though, it was just kinda scary seeing all that smoke, and no, I didnt drive anywhere, I wasnt that drunk.

 

[Chads93GT]

Well, if you suck a can of seafoam through the intake to clean out the carbon in the lower intake, valves and combustion chamber, its going tos moke like crazy. The worse thing that will happen is a fouled plug. I have had that happend before.

 

[Modded]

I just took my throttle body off and used CRC TB cleaner to clean the thing thoroughly, front and back.
Also used CRC MAF cleaner to clean the sensor.

 

[dec322]

I just took my throttle body off and used CRC TB cleaner to clean the thing thoroughly, front and back.
Also used CRC MAF cleaner to clean the sensor.

Well, I tried to pull the TB off and it wouldn't pull off easily. I only found two nuts to pull off...it seems like there should have been a third under the left side. I couldn't find one and didn't feel like spending alot of time on it (only had 15 minutes).

I just used the deep creep seafoam spray and sprayed the mess out of the tb. I turned the plate and wiped out as much as I could and then I sprayed alot through the tb. Started the truck and revved it up a few times. No smoke. Then I drove it around and it has been fine. I'll give it a few days before I call it fixed.

I do still need to clean the maf. What is CRC?