2003 G35 coupe. Runs great up to 40mph, then doesn't go any faster. Was told by previous owner that it was the transmission speed sensor, but can't provide proof. Any ideas? Didn't notice any cel on.
Thanks

 

Sorry, more info on car. It's an automatic, fuel gauge points straight up like it's REALLY overfull, coolant temp gauge is inop, the AC controls won't turn off AC and the radio system won't turn on. Do y'all think all of this might be related to not being able to get above 40mph? Any help, or a direction to look in, would be greatly appreciated.
Thanks again

 

Have you used any sort of OBDII code reader on the car? You can get a cheao one that will work with your phone for cheap on amazon:

i.e.

 

I haven't checked yet, due to no cel. Plus, I don't think a generic obd2 scanner will read anything but engine codes. I'll try it in the morning.
Thanks

 

You have a car that basically doesn't run and isn't throwing any codes? You could push it off a cliff and collect the insurance or limp into Nissan and ask for help!
Gary

 

Turn the key to the on position with the engine not running, check to see if the CEL light even illuminates on the dash during the pre-start indicator check. It's possible your CEL is not functioning at all.

 

Why did you buy it without having it checked out by an Infiniti dealer prior to purchase?

Telcoman

 

+1... I've seen unscrupulous sellers intentionally crush the CEL on cars before in order to sell them as "CEL not on".

There could be a cut wire, bad ground or voltage regulation problem... but I suspect many of these electrical problems are related.