My truck has always had horrible throttle response off idle. You can move the pedal a lot and the truck won't move. It will some times stumble then take off, or just do nothing than take off. I'm trying to figure out if this is due to a bad tune, or a vac leak, or maybe just the dr x harness. Any ideas?

I still want to get under the hood with a can of starter fluid and spray everything to see if I can find a vac leak.

 

The X-Link cannot affect throttle response. If it could, and did, you would be throwing codes.

Can you post your tune or throttle response tables?

 

It's in the tune IMO. I'm on the other end of the specturm, my throttle is a little too sensitive. If I'm cruising on the freeway and hit a small bump or something in the road my foot will lightly cause the pedal to move and my truck starts to surge. Kinda annoying. But a buddy told me what table it was I needed to adjust in the tune but I forgot what it was.

 

In your case, it might not be so much the tables as much as it could be just a weak spring on the peddle assembly itself. GM started slowly increasing the spring tension throughout the years due to complaints just as yours. Mine being an '01 had an extremely touchy peddle and just as you described, if you hit a bump, a blip of the throttle later you had whiplash...LOL Actually though, I know of several people that just upgraded the spring on the pedal and it seems to help quit a bit. It's really easy to do as the spring is on the side of the assembly.

 

Didn't look into that. I guess before I deal with the spring I'll try the tables, if that doesn't help then I'll do the spring.

 

x2, i added another spring along side of the stock one and it helped the throttle blip happenings when going over bumps etc..

 

god its so annoying in a bouncy truck. I wedge my foot into the side of the floorboard hump for some stability on the throttle position

 

I think it may be in the tune, but I'm trying to weed out all other possabilities. Like for instance this morning the truck ran like a rape ape, throttle response was awesome, truck shifted great, and it pulled great. As soon as the pedal starts moving the engine revs up. Other times its numb and it takes a noticable amount of pedal movement to move and on a down shift the rpms jump and jsut hang there and don't climb, almost like its working just at hard to keep speed at 3k as it was at 2k.

Yet today while it ran great, just under small acceleration and a down shift from 4th to third (didn't get above 3k rpms) I got 7deg of knock retard.

I'm also very inexperienced with tuning, so I may not know what to look for when it comes to correcting the problems. My ltft are anywhere from -3 to -10 when crusing some times.

 

Sounds like it could also be timing being pulled. Might even be related to your trans tables. Plenty of possibilities in the tune. Can you post the log with the KR?

 

I'll try to post logs this weekend. This week has been busy with the house buying stuff.

This on/off nature of the truck really baffles/frustrates me. After start up, any throttle tip in makes afr go lean(17:1, then rich (13:1) and the truck stumbles. Some times in PE AFR is 11.5 and some times its 10.5. Some times the truck down shifts and it takes off, some times it doesn't. I would swear its a whole different truck