I have a Outback 2005 5MT. I just changed my driveshaft to fix a bad U-joint. It is freshly tuned up with full fluid changes (including rear diff and trans), plugs, wires, ect. There is no CEL or any indication of issues. This problem occurred intermitently before, but now it is constant.

I engage the cruise and the car pulses acceleration wise. If I let it continue, it cuts out and blinks at me, yet clears on next restart. No code remains to read. The MPG will reflect the pulsing to the tune of 5mpg or so.

I would normally lube up my cables and see if that fixes it, but there are none. The pedal is a little stiff, but not what I would consider bad enough to cause issues. Also I have little info on how the cruise works on this model and the Haynes manual is vague. I have searched for a vacuum leak and found none.

Can someone guide me to the next step here?

I had one have problems like that but it was indeed a vacuum leak. I couldn't hear or feel it though. It was on the back side of the actuator right where the hose connects. There was a small crack at the very edge of the nipple.  But it sounds like it could also be your neutral safety switch. There was a issue with the NSS washers being too thick. I've hear of people having luck with either shaving the washer down real thin or buying a new one that's thinner. One person mentioned on a  thread that he used a .030 copper washer and it fixed his problem. Good luck

drive by wire? some people have had to replace their pedal assemblies. You might search for those threads.

 

my 06 WRX is DBW - trouble free so far. Didn't realize 05 was DBW on outback  - or I forgot.

 

their may be some type of code stored that requires the SSM or different protocol to read.

Thanks, I will dig back into it tonight and see if I can find a new leak. Also I will go through my rather immense and horribly organized washers to see if I have a shim that might work. The pedal assembly is probably the most expensive, so I might save that for last.

If expensive, for a part that's a rare failure and easy to replace just install a used one. Put that cash into significant failure items like timing pulleys, new brake clips, new Subaru fuel pump and alternator.