jamesdal7

I have a 1998 Chevrolet Truck C1500 1/2ton P/U 2WD 5.0L SFI. I came up with a problem yesterday while driving on highway. After driving at 65 mph, truck slowly starts to slow down, all the way down to 30 mph. I stopped bought a new gas filter and changed it. It started fine again and ran fine for a couple of hours just fine. Then starts to do it again. I stop the engine and re-start and it's fine again for another hour or 2.

I don't think its the fuel pump, could it be?

Ok, I wanted to give a little bit more info. When I press the the gas pedal, I get no response. It just stays idle, I put it in neutral and kill the engine. Start it back up and it stays fine for few hours. Could it be some sensor?

silverado08

sounds like a short in the fuel pump.

jamesdal7

But if it was a fuel pump short, wouldn't it stop the engine? I engine never shuts off, it stays on, when I press the gas pedal, i get no reaction, it's like i'm not even pressing it. Once I turn off the engine and start it back up, its fine for a few hours.

therewolf

Just a question, this may be unrelated. Any possibility your gas cap isn't venting properly?

When you fill it up with gas, do you top it off, possibly overfilling the tank?

This sounds like vapor lock to me.

jamesdal7

OK, my light turned on and took it in, and it seems it's the mass air flow sensor.