Strange Random Low Idle

[Jordan836]

So latley ive been noticing my 03 SS has been randomly idling lower than normal like sometimes to the point where it seems like the truck shut off, sometimes it will dip below 500 rpms but then bounce right back up. I notice it more in real slow stop and go traffic like the other day I was driving though a parking lot and id be on the gas off the gas and when I would let off the idle would dip way down and my friend was with me and he noticed it too and thought my truck shut off so I had to drive double footed because it almost seemed if I didnt it would stall. Then I shut it off went in the store and it seemed to be normal. I also notice every morning when im in the dunkin donuts drive through my pacesetter Lts rattle on the frame on the passenger side so sometimes to make it not rattle when im in the drive through ill just hold the brake and give it a little throttle and it will stop the rattle but as soon as I let off the idle dips down to 500 rpms sometimes a little lower. It also seems to happen when im in the drive through and if I tap the breaks and the front of the truck tilts forward a little the rpms will also seem to drop. So I was thinking maybe my throttle body was dirty so this morning I cleaned that and there was some crud in there but then I just drove it and it didnt really seem to make a difference? Im not sure what else it could be. I was almost thinking something with my tune? I also thought something was up with my tranny because it would seem to get stuck in first or second gear and I brought it to my tranny guy and he hooked his scanner up and couldnt find anything wrong and he also brought up the fact that maybe something it funky with my PCM and that was what might be making my tranny act up since the problem with my tranny was very intermitant. The PCM is tuned by nelson performance and ive usually had really good luck with the PCMs he sends me but I have been thinking about giving Wheatley a call and having them do a PCM for me to try something different but I just dont feel like spending the extra money at the moment and I get free retunes from Nelson so I might just have to get another PCM from them. Id prefer to do nothing with the tune as of right now unless I have too because I plan on getting it street tuned in the spring but if my tune has something to do with my idle problems I guess I wont have much choice. But I just dont see how the tune can change itself all of a sudden because it was perfect when I got it done in september, basically im just looking for some ideas on what might be making my idle all funky! A little more info on the truck its an 03 SS with pacesetter Lts no cats custom 3in Y pipe then the tranny has a transgo hd-2 shift kit vette 1-2 servos and a sonnax billet 4th servo with a billet accumulator piston and a nelson tuned PCM.

[Cramer]

Might be your fuel pump. My old work truck would so the same thing. Almost sputter to a stop when your going slow or in the process of a slow turn. It would stall out when at an idle sometimes too. That truck went through 5 fuel pumps in 2 years.

I highly doubt it's your tune since you had no problems with it till now. Tunes don't change themselves other than the adaptive learn and fuel trims.

Try testing the fuel pump first. I don't know how to but someone might be able to help you.

[Jordan836]

I never thought about the fuel pump but thats a good thing to think about. I was also kind of doubting it would be the tune as well just because like you said they cant change themselves. Now would a bad ground cause something like this? Just incase where are the grounds located on the SS I know theres one under the hood but where are the others if there are others? It wouldnt hurt just to check those anyways.

[70chevy03ss]

Mine used to do this when I would pull into a parking lot..

First i would look at you throttle body. It probably needs to be clean.

At the same time I would clean the maf

Also wouldn't be a bad I idea to change your fuel filter located under the driver side door...

Also Justin from Black bear did say something up this year truck 03 has this idle problem or hiccup. Try this things first..

Edited December 12, 2010 by Sick03ss (see edit history)

[Jordan836]

Ya I was thinking throttle body too, I cleaned that yesterday and it didnt really seem to help. I'll try the MAF though. How much of a pain is it to change the fuel filter? Anything important I need to know when changing it?

[70chevy03ss]

Not hard at all. Just take your time.

[Jordan836]

Ok it sounds easy enougfh.What did you end up doing to yours to make it idle normal?

[70chevy03ss]

Mine was the throttle body. It had a bunch of carbon built up on it. Clean the maf and put some lucas fuel add.

 

If none of that works check you battery maybe a loose connection??

[Jordan836]

Ya I"ll check all that stuff. Would it be possible that the battery thats in it is too small? I bought the truck used back in september and I havent really looked into the specs on it. But now that I think about it the whole idle issue started happening only a few days after I hooked up my amp and subs in the truck, the battery looks on the new side but is there a possibility that it just doesnt have enough juice for the SS? And ive read some people use that seafoam stuff to clean out engine internals any idea how that stuff works? Or just use the lucas fuel additive?

[alex.t]

seafoam works good, you can check there site for all procedure, i had the same issue and had to take off my throttle body and open the flap and clean everythign out with carb cleaner, i also did the maf and air cleaner. i doubt its your stereo, do you have somethign to check and see if your battery and alternator are good?

[Jordan836]

I dont personally have anything to test the battery no but Im sure I can find someone with all the right stuff. The air filter on my truck is a brand new K&N one so I dont think its anytihng to do with that. Im going to clean the MAF and maybe try some seafoam. The only thing that made me think maybe the battery doesnt have enough juice is because the problem started a few days after I installed my amp and sub so maybe the battery doesnt have enough juice to power everything it has too. I had optima yellow top on my 5.3 silverado and it was awesome. Im not sure of the specs on the battery thats in the truck now ill take a look in the morning when its light out.

[70chevy03ss]

I would take the battery out and have it checked. Never now stranger things have happened. Also you said that it a new K&N filter the maf might have the oil stuck to it.. You might just have a battery that has a bad cell. What does your gauge read when you have the system on and the truck is running???

[Jordan836]

Ya I was thinking it might have got a little oil on the MAF. As far as the gauge reading it reads at about 14 right in the middle of the gauge. Do you think if I were to bring it to the dealership theyd be able to hook their scanner up to the truck and theyd be able to tell if something electrical is acting up? Would a faulty ground cause something a low idle due to bad signals getting sent to the fuel pump etc.? How many grounds are on the SS and where are they all located? I figure it wouldnt hurt to check them!

[Fireman31]

Since you already cleaned the TB, clean the MAF, then have your battery and alternator checked by your local auto parts store(many do it for free). Did you install a power cap with your new stereo equipment?

[Jordan836]

Since you already cleaned the TB, clean the MAF, then have your battery and alternator checked by your local auto parts store(many do it for free). Did you install a power cap with your new stereo equipment?

 

 

The way I have the stero set up is I have the 4 gauge power cable running off the battery then it goes into a fuse/fuse holder then through the firewall and ran to the amp on the back wall behind the back seat. I had it set up just like that in my other silverado and I had no issues so thats why I ran it that way this time.