All,

My fiance was driving my 2004 G35 on the freeway when in the middle of driving she felt the car go into limp mode. The car's power stayed on but when she pressed the gas pedal the car did not accelerate or respond and the car started to coast. The car went from 65 mph to about 40 mph due to the coasting and she eventually had to pull over on the freeway. When she pulled to the side, she turned off the car. When she tried to restart the car, the check engine light came on, and the car would start for a brief 1-2 seconds but would then die. She tried about six times before the car finally started and she was able to drive home (she said the car felt normal and was able to go 65 mph). When she was driving back home the check engine light was there initially but eventually disappeared. When I got home, I took the car to auto zone and it felt like normal. I did the OBD diagnostic and nothing came up, probably because the check engine light was gone.

From searching for limp mode, most have check engine lights where they are able to read a code and figure out a solution. I have no code and don't know how to proceed. The limp mode happened a few months ago, and I had to change the cam shaft sensors and while changing those I also changed the starter and spark plugs. Any idea on what is causing this? Throttle body sensor? Any recommendations would be great before I have to shell out $100 to go a shop that can do a OBD diagnostic with memory.

Thanks all.

 

It's always recommended to change all 3 sensors when you do them, 2 cam shaft sensors along with the crankshaft sensor. You can always go to a local pepboys, oreilys, or whatever parts store is near you and have them scan the car for you which in most cases they'll do free of charge.

I'm sure it's something simple, these cars aren't to complicated to work on or diagnose.

 

I went to autozone and did the OBD reader/diagnostic test and nothing came up. The check engine light is no longer on, so they weren't able to get a read. That's why I am a bit confused on what the problem could be.

 

I would buy yourself a good scanner for 100 bucks and you'll never need to go to another place again. I recently purchased an Autel Diaglink for about 115. It does normal ODB2 things, but then you can purchase vehicle packs for an extra 15 bucks. I can read just about all the modules in my 06 coupe now without any issues. I've used the scanner and read vehicle specific modules on my Audi, Infiniti, and Toyota.

There should still be freeze frame data stored, so why Autozone couldn't read that I'm not sure.

Are the sensors you bought OEM? I know the car has problems with aftermarket ones.

 

Code scanner + search function here ftw.

 

Got a Bluetooth OBD2 scanner (basx) that works perfectly on this car, requires the $5 Android app torque for full functionality but it costs a total of $28 for the two.

As for the limp mode, start with all the low hanging fruit, fluid levels, check spark plugs, etc. Hopefully it's something obvious, if not the OBD2 scanner is well worth it and BT ones for your smartphone are cheap.