Need some help here...I have a 1999 Suburban w/113K on it. EVERYTHING has been serviced (that I can think of) but when you get in it first thing in the A.M., it hesitates when you first accelerate (for about 2-4 seconds.) Kind of like it's missing or flooding out. Outside temperature doesn't seem to make a difference. It runs like a champ after that first hesitation. Any help would be great!!!

When you say "EVERYTHING has been serviced " what does that include? Have you had the injectors cleaned? Rough idle and surging can be dirty or sticky injectors. If you haven't changed your fuel filter try that first. If that doesn't help consider a fuel system flush and injectors clean up.

Thank you for your response!

I haven't actually had the injectors serviced, but I have been running AMSOIL fuel injector cleaner for about two years now (other brands B4 AMSOIL). The idle is actually smooth, just hesitates when you first accelerate. Also, I've replaced the fuel filter numerous times (WIX), and I have even replaced fuel pump (AC Delco)(that was fun).

I just recently had the trans serviced 'cause the wife said it was shifting hard. I think this is something common on this truck. The trans guy said it was still throwing a code, so I may run it down to my buds at Oreilly's and have 'em check it out.

try cleaning your throttle body. sometimes you get build up in there and it can cause hesitation, have you done a full tune up on it lately?

Need some help here...I have a 1999 Suburban w/113K on it. EVERYTHING has been serviced (that I can think of) but when you get in it first thing in the A.M., it hesitates when you first accelerate (for about 2-4 seconds.) Kind of like it's missing or flooding out. Outside temperature doesn't seem to make a difference. It runs like a champ after that first hesitation. Any help would be great!!!

Mine does the exact same thing (2000 Z71). BUT if I let it warm up before I take off it doesn't do it, but I never get up early enough to let the truck warm up :lol:

Ok, my mistake here. I saw it was a 99 but didn't notice you said 5.7. I was thinking 5.3.

bluewhitepete is correct. If it stumbles at take off then it can be a sticking butterfly in the throttle body. They get a bit of carbon build that makes them bind just a bit when they first open. I had one that the shaft on the TB was causing the problem. I lubed the external linkage and it smoothed out.

See if that helps.

Also check your EGR valve. The hesitation off idle can also be traced to a sticking egr valve.

Where is the EGR? That's one thing I haven't done, but have thought about. Is it easy to replace? How about $$

Thanks, Clay

It is on the intake, but not sure where.