i have a 1997 sd with 132k on it daily driver for work. drive 14 to 20 miles to get to work at top speed of 55 runs fine . took it on the highway to visit daughter at college 35 miles into the trip at 70mph lost power started hesitating badly would only go 55 mph got off the highway drove on back roads at 55 ran fine. on the way home on the highway about 15 miles in did it again then came out of it for a couple miles before doing it again,drove the rest of the way home at 55 on back roads no problems. the only code its throwing is for the abs. has new plugs and wires 5 weeks ago. local mechanic said clogged cat or bad sensors ? looking for any advice on where to look for problem (electrical / fuel????)

 

Well, tough to pinpoint. Fuel pump and/or sock filter, canister fuel filter, vehicle speed sensor, injector sticking, throttle position sensor to name a few right off the top of my head. In many instances you'd get a misfire code or a cat code or a downstream O2 code. What is the specific code it's throwing?

 

the only code was p1317 I think that is for the abs.

 

It is, it's saying you have one wheel sensor with an electrical issue. All you can do is trace the sensor lines to the connector and see if there's any cuts, abrasions, skinned wires or corrosion. That would not cause the cutting out or chop at 70mph.