Help 5.3 hard starting

[FIRECAT]

Guys, I need som input on something.  My 2000 5.3 with about 20K miles is beginning to give me some trouble starting.  It has been fine all summer, but now that it is getting colder, sometimes I have to crank it over several times before it will start.  Most times I have to give it a little gas on the pedal.  This will do this after I have run it for a while, let it sit and then gotten back in.

 

The truck is well maintained and being fairly new, I highly doubt from the way it is acting that it is a fuel injection problem.  

 

Also, when it is cold out when I first start it in the morning, the truck will run, but the RPM's fluctuate between 500-1000 at idle, then it will starighten itself out.  My brother had a '93 5.7 that did the same thing and we never knew why.

 

Anybody have the same problem?

 

Any feedback will be appreciated.

 

Thanks

[chevy4x4trucks]

My truck gave me some probs when the weather was fluctuating as it is now.  Once it was because I was still running 10w-30, but an oil change w/ 5w-30 took care of that.  Otherwise my truck will have probs starting if it's been sitting a long time, or there's been a severe weather temperature change.  Don't know why, it just happens.

[RyanbabZ71]

the fluctuation in rpms when the truck is cold (after sitting a long time) is normal. dont worry about that

[FIRECAT]

Ryan, no offense, but what is happening to me in particular is NOT normal, trust me on this one.  It's almost like the truck is going to stall, and then suddenly realizes this and speeds up the idle.  It's very strange. ???

[RyanbabZ71]

i know exactly what you mean there.  Had it happen about 3 wks ago.  It was like a hiccup.  After about 5 min the truck ran fine again.  This happened after it sat all day.

 

White smoke also came out of the tailpipe.  Temp was about 60 out.

 

What i am talking about is normal is when you start up your truck after sitting over night and it revs between 500-1000 and stays constant.  Then itll settle down to 500 rpms when the engine warms

[FIRECAT]

Never had any smoke out of the tailpipe and usually this happens when its less than 45 degrees out.  Sounds like your describing the same thing, but, I'm sorry, I don't think this is normal.  My fathers truck (same year/motor) and my brothers (99 5.3) never did this.  Plus it will do it even after just sitting for a 1/2 hour.  Like I said, the result sounds the same, but I think that the reason its happening is different.  I really don't know, and I'm not trying to start a p!$$ing match with you here, believe me.  I have owned 4 Chevy trucks in the last 5 years and none of the others did this.

[chevy4x4trucks]

My truck will sort of lull when you put it into drive, you start hitting the gas, the rpm's go down then shoot way up.  It's really a rough start.  Happens after the trucks been sitting for a while and I first start it up.  The RPM drop is noticeable because you can see the headlights dim.  It's odd, but the dealer "could not duplicate"  (well duh, you guys aren't leaving it sit overnight)

[RyanbabZ71]

i think you are misunderstanding me

 

What you are describing with the truck almost dying is not normal.  Mine shot up to like 700 rpms then down to 250 then back up then down and stayed at like 300 for a few seconds then went to 500.

 

What i am saying is normal is when you start your truck and it idles at 700-800 rpms instead of 500 constantly for a few min till the truck gets warm then drops back to 500.  

Sorry if you misunderstood me

[FIRECAT]

Ryan, I know your right about the initial start-up, that I understand.  What mine is doing is fluctuating between 500 and 1000, it does this for 6-10 cycles before its settles in at about 500 RPM idle.

[Shaners]

Have you checked your fuel filter?  Or have you tried a different brand of gas?  There could also be a bad O2 sensor, EGR or PCV valve that is causing the fluctuation.

 

I'd take it to the dealer and see if it coded anything, and if it didn't ask him to give you a portable recorder to leave plugged into the truck so you can capture the info for him when the truck acts up.

[pacodiablo]

beat the motor with a stick, or......get a block heater