Truck Studdddering during Driving

[troonman60]

I have a 70 chevy with a 454 motor with mechanic fuel pump and took it on its 1st long road trip (150 miles) since I have owned it. After driving for 30 mins on flat ground it studdered for aprox 15secs like it was starving for fuel but did not stall out and I was able to continue driving. This continued the whole way, the weird thing was once I started hitting hills big or small the problem seemed to happen more often, losing power for few seconds but never stalling out. I was wondering if u guys have any ideas on what might be causing this.

[riche]

Fuel filter?

[smoky02]

I had the same problem with my truck and replaced the fuel filter and the problem went away for a little while but it did come back. But I was told a few different things that it could be. Could be getting to much fuel, not enough fuel, could be trash in the carburetor. Or just a POS carb. I think that's all the options that i can remember.

[cdowns]

yeah fuel filter would b first to check followed by in tank filter also make sure you have the proper gas cap//check all rubber hoses in the system like the one under the cab and if you have longer lengths(bad IMO) if they're collapsing or kinked or resting on the manifold or block of the engine// if all that is all ok i'd start checking the ignition system and components

[69GMCLonghorn]

I think everybody is on the right track: Just start at one end of the fuel system and start eliminating things. If it was spark related, it would "probably" be more consistent.

Also, check your plugs. The color and wear on them can tell a pretty good story.

[mclairmo]

As the old addage goes, most carb problems are really ignition/timing related. I would focus on ignition first, but that's just my opinion.

[Longhorn Man]

it is rare that a fuel would cause a "studder"... normally it would be a bog.
I would start with a tune up

[DANTIP]

How old was the gas? Fresh gas may do wonders!

[oldcarfart]

Originally Posted by troonman60

I have a 70 chevy with a 454 motor with mechanic fuel pump and took it on its 1st long road trip (150 miles) since I have owned it. After driving for 30 mins on flat ground it studdered for aprox 15secs like it was starving for fuel but did not stall out and I was able to continue driving. This continued the whole way, the weird thing was once I started hitting hills big or small the problem seemed to happen more often, losing power for few seconds but never stalling out. I was wondering if u guys have any ideas on what might be causing this.

Back the gas cap off a notch or remove it all together and retrace your drive. (use the same route everytime you troubleshoot driveability as a known benchmark and make one mod at a time to eliminate multiple variables), often there is no or inadequate venting of the fuel tank to compensate for the fuel being pumped out and you end up with a vacuum on the fuel pump's inlet side (BTDT) always start with the cheap and easy fix's first <grin>