gnuiver

Driving from up north 2 weeks ago. 45 min into the trip 80mph on the highway. Heard a change in the drive train noise. (at first I though it down shifted) No RPM change though, not on a hill. By the time I got home. There was a good vibration in the gas peddle under acceleration. First though was drive shaft CV, rear was done last year. Front CV feels good. Torn boot in the RH CV boot, Casualty of a bearing change last year. Bought both axles and another bearing just waiting for time to do it. Now was time. Lower control arms, struts, bearings and CV shafts done, and alignment. Still no change in the vibration, but the front end is tight now. Changed the front trans axle last year too after the bushings took out the pinion bearing. Dropping the front drive shaft tonight for inspection. Changing EGR valve, i have an intermittent code for it. Rebalancing the front wheels tomorrow as well. Cleared a codes with battery unhooked last weekend, check engine light was on before this, EGR low voltage. Drove to work today and stayed on surface roads and kept it under 50mph. Took it easy. still vibrates. code returned P0507 idle air, and P0430 catalytic flow. Plenty of power. only vibrates under a load....... Plugged Cat's??? Suggestions, thoughts? 245,000 (new heads and chains 8,000 miles ago)