NEW YORK (TheStreet) -- We have seen declines in the price charts of auto manufacturers and retailers so now may be as good time to review the auto parts industry to see if any portfolio adjustments or "tune ups" are needed. With the Wall Street Journal reporting recently that "U.S. Auto Sales Pace Accelerates," one would conclude that there is plenty of demand around to fix older cars and to personalize newer ones.

AutoZone  (AZO) , pictured below, is moving on all cylinders. The price has moved nicely higher the past 12 months and the On-Balance-Line (OBV) has steadily matched the price advance. August saw a sharp shakeout, but the OBV line hardly budged, which means the longs held tight. We like this name.

Advance Auto Parts  (AAP - Get Report) adjusted the throttle the first half of the year, but now AAP is moving higher again with the OBV line confirming the advance.

Snap-on  (SNA - Get Report) has developed a textbook uptrend the past 12 months, as seen in the chart below. The OBV line has shown fits and starts, but prices continue to torque higher. A period of sideways price action could be in order.

O'Reilly Automotive (ORLY - Get Report) , below, has been lucky all year, and prices have climbed steadily. A move through the high around $258 would not surprise us in the months ahead.

Our last chart, below, shows a different story from its peers. Genuine Parts  (GPC - Get Report) has been in a relentless downtrend all year and investors should steer clear of this name until a bottom forms.