Absolutley no recent problems...and putting a lot of miles on it. But, about a week ago, with about 160k miles, it started bucking, the tachometer would jump up and down...lost power, it would recoup and run ok, but a block or two later, the same..the tachometer bucks up and down..it seems like it was getting gas alright. I went over to a buddy and looked things over...found the air intake-elbow was cracked from heat/age and sucking air in. Found the part and waited a few days to get it delivered. Replaced it, cleaned out the soot...it ran fine for about 30 minutes and took it on the interstate and again, started bucking.. I hobbled home down side streets.
Its not throwing out any codes.
Could it be the cat converter, or the distributer, or something as simple as a dirty fuel filter?