When I start up the truck after sitting for long periods (8 hrs etc), it has weird driving habit. It acts like its not getting fuel when I push on the gas. Example, say if the gas pedal was rated from 0 to 100 and 0 equalling no gas applied and 100 being WOT.
When I put it in drive and start leaving my driveway driving around 5-25 mph is where is happens the worst. When I push the gas pedal from 1-25 it feels like I'm not even pressing the gas but once I get past 25 the truck will lurch forward like I just punched it. So basically I have to give it more than a 1/4 throttle or else the truck lurches constantly.

Now once the truck gets up to operating temperature, it will drive completly normal.
Anyone have any ideas on what I should look for first?

 

I feel you're pain. Mine does the same stuff.

 

Dirty/sticky throttle body butterfly? TPS going bad?

 

Could it possibly be related to the TrailBlazer stall?

 

Trucks only got 30K miles and it never did it before with the 5.3.


No I really don't think so, because it never really did this until I got the dyno tune so I believe its something in the tune.

I wish I had a WB02 so I could see if I'm running way rich or what in the mornings.

 

Ummm... never did this before, but I guess there's always a first time.

"Wing of bat, eye of newt,
Chunk of copper ore from Butte.
Be it truth or be it lies,
Let this thread arise...Arise...ARISE !!!!!!!!!!! "

 

It does have ETC (electronic throttle) right?Reason I ask is you have an 03 which has ETC but not sure what year engine you put in and if you went back to cable?
Have you logged it when it is doin this?
If you can or want to sent me your tune and the logs if you have any while it is doin this!

 

Ah good! Now that I've brought this thread back from the dead, I have the same problem. It happened after I got the Radix, and turned the idle down because it was way too high. I changed the base airflow table from:

GEAR 19.38 17.89 16.37 14.9 13.64 12.28 10.92 9.66 8.35 7.09 5.3 5.3 5.3 5 5.5 5.5

P/N 16.4 14.5 13.11 11.95 10.98 10 8.98 7.98 7.2 6.21 5.3 5.3 5.3 5 5.25 5.3

to:

GEAR 18.04 15.95 14.42 13.15 12.08 11 9.88 8.78 7.2 6.21 5.3 5.3 5.3 5 5.25 5.3
P/N is the same.

This helped some but did not completely cure the problem. Well, today I observed my wideband while the engine was cold and acting up this way, and noticed the AFR was going WAYYYY lean, like off the scale lean! I'm going to try reducing the airflow a bit more, but does anybody know what else might be causing this?

 

Vortech350, you're too fast for me. Yes I have ETC also. I didn't mean to crowd in onto Zick, but was doing a search on the issue and this thread popped up, so I thought I would revisit it.

 

Man do I feel like a dumb ***,this thread is old.LOL
GMC do you have any logs?