Smooth idle, but seems rough at ~55mph+
 

Hi,

Today I drove my '80 SC from Portland to the coast, about 100 miles. Toward the end of the trip, it seemed that the engine was running a bit rough when I was at highway speeds or even a little below. Last weekend I installed a new fuel accumulator to correct my hot start problem - that definitely did the trick for the hot start. I took it for a test drive and then drove around town a bit last weekend, but today was the first time I had it out on a long drive. I only started noticing that it felt rough in maybe the last 20 or 30 miles. It felt almost like it was missing or something. However, I only felt this while driving close to and above 55. I didn't feel it while driving slower through town. At idle it runs smooth. I'm wondering if this could be something to do with my accumulator repair - or if maybe I'm just paranoid. Thoughts?

Thanks,

Todd

Doubtful it's related to the accumulator (unless you're leaking fuel and then you'd notice that in a hurry...)

I'd check for loose vacuum hoses first and then ignition (wires, plugs, timing, etc).

Thanks fanaudical - good points. The plugs are overdue (in time) for change and the oxy sensor is well past due for a change, so I'm wondering beyond the visual inspection for obvious things like loose hoses or wires if I just need to start in on the tune-up.

Thanks again, Todd