The subject may be an old one, but since I am new at this I’ll just try and put it out there. I have a 1998 Chevy truck that runs well for about 20-30 miles, or it warns up real good. Then it start to lose power. When you give it gas it acts as if it wants to die, and it will eventually lose speed. The speed is reduced slowly over about a 15 minute timeframe, and the vehicles acts as if it will not accept gas. Eventually I’ll stop, kill the engince, let it rest about a minute, and the truck wil crank up,and run fine for about 15 more minutes, and the same thing happens all over again. I have replaced both O2 sensors, and the fuel filter. What in the heck is going on. Please help!
Next step is to check the fuel rail pressure WHEN THE PROBLEM IS PRESENT. On some engines, you can do this with a tire gauge…Low fuel pressure means fuel starvation.
Will the engine idle properly when the power drops off?
The engine idles fine, it only wants to stall if you try to give it gas or increase speecd.
Where do you check ‘fuel rail pressure?’