Odd driveability problem

[dog paw]

Let me run this by you folks, maybe someone else has pulled there hair out also.Have a 04 Vibe GT all stock 70k miles. Every once and a while it will throw a fit @ highway speeds. Starts a "lean type" surge/chuggle. If the cruise is on on a incline you will find the pedal to the floor. when the load changes it will "catch up" hard and the cruise will over correct. This will happen with or without the cruise its just more noticable with it on. Tech 2 shows no abnormal readings whatsoever. Put a fuel pump and filter in and the injector cleaning routine to no avail. Being a bit of a cheapscate I'm a bit hesitant to start throwing Mass air flow sensors and other parts at it willy nillyI would swear it was junk fuel but it happens at random with any type fuel

[engineertwin2]

This is common of most cruise controls. In the GT, it does not have the ability to downshift (being a manual transmission). This result in a leaned-out bogged-down feeling. Cruise control is not designed or intended for use in maintaining speeds on inclines (or declines, although it does better jobs on declines). In an automatic, the transmission automatically downshifts to compensate.If this is occuring on level ground, have you tried disengaging and re-engaging the cruise control? At what speed do you consider highway speeds (to some it's 55 to others it's 85)?

[dog paw]

It's most noticeable to me @ 70/75 It will do it with the cruise off also. Might try to get a couple snapshots on the Tech 2 (again) and see if something shows odd. Been this road already though. The only wrenching this vehicle has had on it is a valve lash check @ 50k Been a good ride