I was coming home one day it was about 71 miles to my house once I got their everything was fine I got home went inside and came back out to go to the store as soon as I started the truck the check engine light came on and it said "reduce engine power" and it was idling rough and when I gave it gas it wasn't letting me high rev. So I decided to park it and figure out the problem tomorrow since it was to late. I woke the next morning and started it back up again and sure enough the check engine light was still their obviously ....then I decided to drive it and the problem had went away and then the check engine light went away on its own. Afterwards, about two weeks later I take that same trip and about 3 quarters of the way their on the freeway we come to some traffic and out of nowhere when we come to bout four stops on the last stop the truck turns of and I immediately started it back up and it started fine but when I gave it gas it was sputtering so I pulled over. When I was on the emergency lane I decided to turn it off and back on and it was idling fine but as soon as I gave it gas it sputtered so I decided to drive it off the freeway like that and I was flooring to get out and half way trough me steping on it started driving fine but the check engine light was still their. So I decided to drive it to my uncles house that was about 15 miles from were I was at in traffic but no problems occurred again.I ran the check engine light and it gave me P0171.So I need help or what to do.

 

Dirty mass air flow sensor(doubt it but easy to clean in case it is), possible vacuum leak(also not as likely but a pain if it is), or a bad o2 sensor. Driver side front I believe would be that one

 

hmmmm... in the fuse box under the hood there is a "engine" fuse. I have pulled this fuse on both of my burbs (first time by accident). It makes the motor idle low and rough and when you step on the step in Park, the motor only revs to 1700~1800. Try pulling it and see if it runs any different.

I can unplug my mass air flow and drive just fine in my 07. The only prob it has is the 1st to 2nd gear shift is REALLY firm! The rest of the shifts are still much firmer but no where near as firm as 1st to 2nd.

 

So I drove it today again and I got to my location and everything was fine but when I decided to drive back my car turned off and I would try to start back up again and it wouldent start so I had to tow it home so now im car less I really need help you guys...please

 

Usually, when you shut the engine down for a few minutes, that message will go away, and you'll be able to speed up. I know this by experience. Go to the main page and do a Site search for this, it has been discussed a lot here. As far as it not starting, that implies more than one problem.

I am quite pro GM/Chevy, but the result of this condition/problem, and the Rev Limit issue, really ticks me off with GM Engineering.

 

Might want to start with checking the fuel pressure... if you've never replaced the fuel pump in this vehicle its probably about due... but check it first...
should be 55+ and should hold when the key is turned off and not bleed down too quickly...
Do you hear the pump come on when you turn the key but don't crank?

 

Well today I decided to switch the fuel pump, fuel filter, transmission filter,serpentine belt, spark plugs, spark plug cables, clean out my intake manifold, clean my MAF sensor, do transmission flush, so ill keep you guys updated to see what happens.

 

Just a tip here, but...
When you're having problems, it's not a very good idea to do too much at one time. Do it a step/item at a time, check your progress with each. If something goes wrong, it can get very complicated deciding just where/what happened.