1997 gmc 350 vortex runs fine if you dont go past 14 trottle when you give it more gas then it just lays down and will not go tuned it up but did not help what could be wrong?

Answer 1

Possible clogged fuel filter or bad fuel pump. If the fuel filter isn't new, suggest you change it first. If no help, have the computer read for codes and see if a low fuel pressure comes up. In that case, it's your fuel pump. Hope that helps. Had the same problem, changed fuel and air filters and cleaned Mass Airflow Sensor and problem was solved. The MAF is in the air inlet line from the air filter box to throttle body. You can remove it fairly easily with screw drivers by loosening the hose clamps. You need to unclip the wire harness as well. The MAF should not be carboned up and you should be able to see clealy through the screen. If it looks black and has carbon it needs a cleaning. Use carburetor cleaner. Don't drive the truck without the MAF in place. The fuel filter is under the truck on the frame rail just about under the driver's seat. It is mounted securely but it does come off. Watch out for spilled gasoline when disconecting, release pressure by opening gas tank cap first. You could also go further and change the ignition wires and spark plugs. I did this too and was amazed at the renewed horsepower. Hope these suggestions help.