03 burb won't idle

**cliffdavis1** · 12-06-2008, 09:07 PM

My 03 suburban starts fine but then the idle speed starts to bounce up and down erratically. It is not a gradual drop, it is a very fast drop like it is being shut off then it rebounds before it stalls. It is an itermittant problem and does it when cold and at temp. Occassionally stalls while sitting at stoplights. Anybody have any ideas?

**JMoney02** · 12-07-2008, 02:12 AM

Any changes made to the vehicle before this happended? Was it all of the sudden? Conditions change
in your location? Did you just get Fuel recently? CEL on? What engine type does it have?
Jeff

**ct9a** · 12-07-2008, 03:56 AM

If it was a Honda I'd tell you to look at the Intake Air Control Valve, but I don't know if GM uses those. Vacuum leak maybe?

**JMoney02** · 12-07-2008, 05:08 AM

Actually they do use the IAC/IAT.......

Jeff

**wesleytravis** · 12-07-2008, 09:42 PM

my 03 sierra was acting the same way recently, i got a spry can of B-12 and cleaned the throttle body real good. i unbolted mine and got it good inside and out. runs like a champ now

**cliffdavis1** · 12-08-2008, 01:32 AM

I have a 5.3 flex fuel. I've cleaned the maf with maf spray cleaner. Ran a can of lucas fuel cleaner in the gas tank. Scanned the codes and I have codes: 101, 171, 174, and 446. It's been doing this for over 6 months but just recently got bad enough to bother me. It does this weather it's warm or cold, wet or dry. I think I might try the throttle body cleaning. It did get worse recently after I ran a tank of flex fuel through it. This is only the 2nd tank of flex fuel that I have used. First one was over a year ago. Same gas station. Runs like **** on flex, no power, bad milage. Engine light did come on after tank of flex was burned. Changed the air filter yesterday. Put a stp paper filter back in. Was running one of the expensive orange oily paper one's. It was still clean but I've read bad things about the oiled ones. This wasn't a K&N but it was oiled paper heavy duty. The guy at Auto Zone turned the engine light off for me and it ran great immediatly after that, more power and no rough idle. Only lasted a day before it started acting up again and light came back on. Filled up on regular fuel and put another can of cleaner in the gas tank. Different brand this time, I think it was STP. I'm going to try seafoam next, heard good things about that brand. Only drove it about 50 miles so far on this tank. Like I said before, there is no pattern to when it acts up and it only does it when idling. No misfires while driving. I also have headlights and guage lights that flicker for no reason. Bad speedometer, Tranny tends to slip occasionally between 1st and 2nd then bangs hard into 2nd. I love this truck but for this price I didn't expect all of these factory defects. I need to keep a log, more than this has happened but my mind is slipping also.

**Kamd91GMC** · 12-08-2008, 02:29 AM

i know this is going to sounds awfully off the wall, but it's something to think of. My Dad's 03 had the FlexFuel in it...our ECM wen't bad. We took it back to the dealer and traded is straight across for his 98' Chevrolet K-1500 LWB 4x4 w/ the 5.7 Vortec backed by the 4L80e Auto and a 4:11 Detriot Posi'd Rear end. only had 91k on it

**JMoney02** · 12-08-2008, 02:32 AM

You are more than one store I've encounter about the FLEX FUEL dilemma. Appears to cause several
different problems that you've mentioned with yours, others. Yes keep a log so you know what you have done,that way your not stepping on yourself. Keep with the regular gas for now if you can. Oil filters are good, if you oil only from the bottom, let dry to the pleats(just can't oil and put back) and don't staturate, not necessary. Use the seafoam if you haven't yet, it'll clean up the inside(fuel, vaccuum) areas. The electrical with the dash, have you had it apart? Someone before you? If you can,
see if move any harness under the dash and see if it flickers the lights, have a Bro help, I know can't see and wiggle at the same time. Seems that there may be a connection problem to the back of the cluster, or with the dimmer switch... Let us know......

Jeff

**cliffdavis1** · 12-15-2008, 07:18 PM

I had a can of spray cleaner and I started to spray the throttle body. The red tube on the end of the spray nozzle wanted to see what was inside of the throttle body so it shot off of the end of the can and went down inside. I had to take the throttle body off to get it out. At least I cleaned it really well. Runs a little better but still stalls. I bought a cheap code reader and 101 MAF keeps coming up. I ordered a MAF off of ebay and will post if that was actually the problem. Oh, bye the way, the vacume line on the throttle body has antifreeze in it.(I thought it was a vacuum line but it wasn't) LOL. Next time I'll make sure that the cooling system doesn't have any pressure in it before I remove it.

**JMoney02** · 12-16-2008, 08:18 AM

Originally Posted by cliffdavis1

I had a can of spray cleaner and I started to spray the throttle body. The red tube on the end of the spray nozzle wanted to see what was inside of the throttle body so it shot off of the end of the can and went down inside. I had to take the throttle body off to get it out. At least I cleaned it really well. Runs a little better but still stalls. I bought a cheap code reader and 101 MAF keeps coming up. I ordered a MAF off of ebay and will post if that was actually the problem. Oh, bye the way, the vacume line on the throttle body has antifreeze in it. LOL. Next time I'll make sure that the cooling system doesn't have any pressure in it before I remove it.

Good you got the code, check thw wiring back from the sensor also, make sure no problems with it also... And now WD-40 has the attached tubes and new head, that sucks Dude.....

Jeff