3000rpm really shouldn't be causeing issues, especially in a 34. General driving I've found my 33 GTST is most fuel economical driving at 3000-3500rpm marks. My Bluebird is similar story and has no issues going well above the 3000rpm mark both cars have 20yr old never rebuilt engines in them. Odd with the fuel smell etc, my 33 is always fuelie but is in desperate need of a tune. Possibly might not hurt to take it to another mechanic just for the sake of a second opinion.