2007 G35 38Kmile, I bought this car last year, but these days the steering wheel bacome harder. I went to the Goodyear, and the engineer told me that there's something wroing in electronic unit. What should I do? I saw some people has the same issue. Does it cost a lot to change the steering angle sensor?

Vickeyduck, if you still have a warranty on your '07 G35 take it to the dealership and let them fix it for free. I'm not an engineer but it sounds like your steering rack might be a fault. Goodyear doesn't have engineers any more than TacoBell does! From his reply he's not even a good mechanic.... Without a warranty take your G to either a Nissan dealership (less $ than Infiniti) or an independent brake/alignment shop in your neighborhood. Good Luck!
Gary

Call me captain obvious but have you checked your power steering fluid levels?

Same thing just happened to my car this past weekend and its driving me insane i cant afford to take it to the dealership and have gone to my local shop and they had no clue what was wrong! please let me know if you figure it out as well thanks!

All right there Captain, if the power steering level is low (hard to miss) then the power steering rack is still at fault due to failed seals.
Gary

What about the power steering pump?

Not always, believe it or not I have seen someone let the power steering fluid become completely drained. Only to fill it almost 10 years later and everything is fine. The fluid does naturally dissipate.

Sorry I don't buy this....^....power steering fluid doesn't evaporate like water, there's a leak somewhere. I've had so called mechanics not put the lid back on the reservoir correctly and the fluid leaked out.
Gary

it doesnt really evaporate like gary said but does absorb moisture out of the air and water is compressible so it would make it hard to turn the wheel.

Exactly....^....which is why Nissan recommends replacing it every 30K miles like all fluids. (except oil every 3500 miles) Hope Vickeyduck post the results when she gets her power steering issue fixed....
Gary