99 Chevy Silverado 2500 was running fine last night..got gas last night but got it from the same gas station as always...thismorning idle was realy rough,shaking the whole truck...really struggling for power too,but it's not stalling...please help!!

which car is it?

problem with 1993 Geo Prizm '99 silverado 5.3 engin will not idle runs at 2500 rpm and drops down to 1000 rpm the back up to 2500 rpm -------------------------

My last silverado was a 99 and i changed out my fuel pump and the fuel pump wiring harness also. That seemed to make mine run smoother

Have you checked the fuel pressure regulator to see if its leaking?

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the problem you are discribing would lead me to belive your fuel filter is clogged which is a simple fix 3 dollar part at any part store or on the worse hand your fuel pump itself could be weak you can open the gas tank cover and have another person turn the truck key to the on position without going far enough to start you will hear a faint whining noise if it is going bad or a louder noise if it is fine Good Luck

you should first test the computer system for trouble codes.you may have overfilled the gas tank and flooded the carbon canister that holds the gas fumes from the tank, i would look for trouble codes first though,as filling the tank and the problem ocurring after that may only be coinsidental,this would be hard for you to diagnos anyway.

Call any chevy dealer and give them your vin. number and they will tell you.

Try cleaning the throttle body and the mass air flow sensor.Does your check engine light come on?

mo me it sounds like low fuel volume i would check my lift pump

This problem can be several things. When your engine is cold, your computer is in a "closed loop" and just pretty much keeps the engine running until warmed up. After reaching operation temperature, the computer starts reading all the sensors. If one sensor is not connected or is defective, you will experience performance problems. Most of the time this will turn on the check engine light, but not always. Second is the fuel pump. This too will cause erratic engine problems.

Check the engine mountain rubbers ,, one or more of them is broken and needs to be replaced.

pop the hood, start the vehicle and move it from park to drive to reverse with the brake pedal down and you will see the engine moving. the broken mounting rubbers are the cause for this.