While on my home on the interstate, I started hearing a noise that sounded like the engine was slightly reving higher in brief intervals. It only occurs when I put my foot in it and maintain a speed of 65 to 70 mph. The tach does not indicate any increase in rpm's when this surge occurs. Could this be LP related? I don't have a pressure gauge. The truck is not losing power and runs fine, just makes this surging noise. Anybody know what it could be?

 

first off welcome to the site, 3 posts & I'm not sure anyone has done so yet..... second, fill out your signature line so we can reference what truck you have, If it is a "sound" or more of a slight feeling I think it is normal engine operation, it being controlled by a computer that is tirelessly checking the rpm and the tps and adjusting to do what you are telling it to. Mine does it with or without the quad box on, so fill out your sig so we can try to help you further.

 

Thanks for the welcome. I have had an apps problem in the past. I reset and it takes care of the idle problem for a while. Probably have to replace it before long. I do not feel a power surge, just an engine surging noise, as if the rpm's are increasing.But like I said the rpm's do not go up when the noise occurs.

 

My father has the same truck as you have, his truck did the same thing when going down the highway at the speeds you mentioned, it did it for a long time and he did not think much off it, but it turns out that it was the Vp44 injection pump getting ready to bite the dust. I would cycle the key three times from the off to on postion without starting the truck and see what codes pop up on the odometer, the code you dont want to see is p0126, this is the injector pump code. For what its worth, he is stock and and on his third Vp44 injector pump, hope this helps

 

Or a P1693 code....companion code to the dreaded P0216 code. It's the only code I got but was still a dying VP-44.
Hopefully, neither shows up.

Good luck

RJ

 

Mine did the same thing for 5 k before it set a code. It showed up as a very slight surge only between 1800 and 2000 rpm at part throttle. 10 k later it was setting codes and mileage was down but still running well. In my case it was the vp44. Good luck!

 

Mine did the same thing it got really bad the truck evern started kinda bucking after a bit but started with the surge vp44 was bad amd the lift pump