RPM Dropout

When I'm driving around 25 - 35 mph and I let off the gas and coast, the RPMs will start going down slowly. Then sometimes they will suddenly drop several hundred rpm and then quickly recover. I guess I'm more aware of this lately because of the power steering whine. I've also noticed this sometimes when I come to a stop. The car doesn't give any codes. PCV valve, fuel filter, spark plugs and wires have been repleaced recently. I'm thinking it might be one of the sensors on the throttle body or the EGR valve. What should I check next?

When I'm driving around 25 - 35 mph and I let off the gas and coast, the RPMs will start going down slowly. Then sometimes they will suddenly drop several hundred rpm and then quickly recover. I guess I'm more aware of this lately because of the power steering whine. I've also noticed this sometimes when I come to a stop. The car doesn't give any codes. PCV valve, fuel filter, spark plugs and wires have been repleaced recently. I'm thinking it might be one of the sensors on the throttle body or the EGR valve. What should I check next?

if i am understanding you correctly...this is normal. the torque converter is unlocking causing the RPM's to drop.

Perhaps I'm mistaken, but I thought the torque converter only locked up in 4th gear above 45 mph.

I think it locks in 3rd gear too.