Hey gang! I know I'll be able to find someone in a group this size and well- informed to help me.
I've got a 1999 Chevy Z71 Ext. Cab with the 5.3 V8 and about 176xxx miles.
Several months ago after driving a long way on a hot day I noticed it would "chug" when accelerating between 40-50 mph but only going uphill. I did not have a load other than myself and a couple of tools tucked up under my backseat. Even if the grade was about 3-4 degrees it would still "chug." (by "chug" I mean it hesitates and lurches, hesitates and lurches at fairly rapid intervals) If it is a flat grade or any other speed (even if it is more than 50 mph) it does not "chug" at all when accelerating.
A couple days ago on a cool fall evening I was accelerating out of town on a black top and noticed it was doing it again this time a little more "staccato" (for those who understand musical terms...if not Google it) and the grade was about 5 degrees (just guestimating). Still no load in the truck. Keep in mind that this is not an on/off ramp type climb it is a matter of a few degrees uphill.
Is this a timing problem or perhaps a fuel line problem? Something serious? Something a quick maintainance procedure will fix? Expensive? Cheap? You get the idea!
Thanks in advance!
G