I have 2007 Suburban, recently starting having a weird performance issue. As I'm driving, doesn't matter the speed, or length of drive time, it starts acting as though I'm losing Engine power, it hesitates, then speeds back up, several times. Some times it's worst then other times. Extreme event, I actually had to pull over, no matter how much gas I gave it, pretty much died. Other times it's minor, like hiccups, power, low power, back and forth. I've had plugs, and wires replaced. Again this happens with no warnings. Drove from Atlanta Ga to Orlando Fl, no problems. Few days started acting up again. Took it to local chevy dealer, they are telling me it's my front left wheel speed sensor. Which that has me scratching my head, what does that have to do with me losing power as I'm driving. This also happens when I'm just sitting idle. Again, it's off and on, no pattern.
Thank you

 

So the dealer found no active codes? Don't suppose you get a check engine light??

 

They are going by what codes are stored in the system.
Could be a erratic gas pedal sensor, acting up but not enough to ''code out''. Common thing to wear also.

 

No, only code was Ft Lft wheel speed sensor and some kind of code dealing with a Manifold sensor, which I figured would be the problem, but Svc Rep said no, it just means your engine is old, and stuck to the speed sensor.

 

MAP sensor, which is in the intake manifold has a big effect on drivability.
Go to a parts store and get a free code scan if you do not have your own scan tool. And write down the codes and research the codes. Engine-Codes.com is a good resource.
There is no working on today's vehicles without a scan tool and knowing the codes. Code tell and point a direction to look at the issue.