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Pulse in steering wheel

I’ve got a 2003 Mazda Protege5 with 103,000 miles. Since having the timing belt changed (although I suspect this has nothing to do with it). I’ve had one of the accessory belts occasionally slipping, mostly with the temperature is below freezing or it’s really wet outside. I retightened both accessory belts myself so, I know they are sufficiently tensioned but, it still slips. I?m not sure which belt is slipping but once it slipped bad enough to emit smoke from under the hood. The other day I noticed a slight pulsing felt in the steering wheel when going along slight bends. With the car parked I applied turning pressure to the steering wheel while revving the engine. I noticed that as the RPMs fell, the wheel would jerk in the direction of the applied force. As the RMPs stay steady or as RMPs increase, it would jerk back against the force of my hand as if the power steering pump were not supplying adequate pressure. I?m thinking the power steering pump is on its way out. Any chance it?s the steering rack instead? Anything I can do to get to a more definite diagnosis? I have not yet tried removing the belt and seeing how freely the power steering pulley turns.

I would certainly be investigating everything about the belt and what it is attached to - including belt condition, proper routing, all of the pulleys, etc. I would also leave open the possibility that something is up with the belt tension, and check for power steering leaks.

My own first guess would be one of those components binding up - maybe power steering, but maybe the a/c compressor (as I think that other than the crank, on that car the steering & ac are the only ones on that belt). Try checking out this wobble with the a/c on vs off & see what happens.

But, in short, until you pull the belt & check those pulleys its all shooting in the dark.

Since the symptoms seem closely related to rpm I’d be disinclined to worry about the rack first.

A belt that has slipped can generate a permanent glaze on it and even though tightened, can actually slip. The occasional grap you get is just the luck of the draw. I would clean the pulley well and replace the belt with the correct OEM belt, and if the belt is getting wet, a shield may be missing from btm of air dam.