wow. violent shaking @ 2500 rpm..
 

hi,

i started my '05 g35 6mt tonight to drive home and i could not get past 2500 rpm in any gear. at exactly 2500rpm the car would violently shake. if i up shifted (which would bring the rpm down) i could increase my speed. luckily i was able to drive home (a short 2 miles). after parking the car i noticed a thick heavy sulfur smell. though, i could not pinpoint where it was coming from (i popped the hood, and sniffed the rear tail pipe but could not determine where the odor originated). it was definitely coming from my car and not from a skunk (which we have plenty of up here).

i know gas can contain sulfur compounds...

is this bad gas? (i bought from a different gas station, but it was a mobil, and it was 91octate or greater -at least the pump said so)...

any thoughts?

get it towed to the dealer
and have it examined

sounds like your car is in "safety" mode. My friend had a problem like yours where his car wouldn't rev past 3000 rpms. He had a air/fuel controller (AFC) in his car and someone broke into his car and ripped it out. the AFC required wires to be tapped in the ECU. so when the AFC was ripped out, the wires were all over the place and his car wouldn't rev past 3000 rpms. so it might be you're ECU or wires being short-circuited...which could also explain the smell you're smelling.

so it smells like rotten eggs? could be something wrong with your catalytic converter.

well, i started it up this morning, and it was out of "safety" mode -if thats what it was (does sound like it, though). i drove to the dealership and dropped it off. will post more when/if i hear anything...

got the car back, and the dealer replaced the air flow sensor (under warranty). -- apparently diagnostic codes p1271 & p1281 showed. though the dealer says they were not 100% positive it was the af-sensor, they replaced it as an educated guess ;-)

anyone know what those two codes mean, or anyone have a reference to the codes and their meanings.?

:edit: found one of the codes over at inifiniti help (http://www.infinitihelp.com/Ownership/Common/codes1.htm)
P1271 Air/Fuel Ratio Sensor 1
P1281 ???

These two codes are for the same thing. The difference is that there are two sensors. One on the left bank of cylinders, and one on the right bank of cylinders. That's why there are two codes. (I just looked it up in the service manual)

so it had something to do with the air/fuel mix...like my friends car and his air/fuel controller.