95 cav bucking
95 Chevy Cavalier. 170,000.
The thing bucks -- either hesitates for a millisecond or surges -- when you put the needle at a steady 40 miles per hour. Does the same thing as you ramp up speed, but the thing is it seems to go away momentarily when you shift to the next gear.
Replaced: fuel filter, fuel pressure regulator, plugs, wires, crankshaft position sensor, and most recently the EGR valve.
Thought the EGR valve was the culprit because I discovered that if you plugged up the vacuum hose going to the EGR valve the car ran perfectly fine, albeit with an ever so slight drop in performance. Nope. Put the new EGR in and still with the bucking.
Tried cleaning the EGR passages -- thought that perhaps they were clogged. Stuck a wire brush down there and tried navigating the corners but hard to tell how far the passage goes.
Anyway, anyone have any ideas?