I need some help with my 06 G35 coupe 6MT with 76000 miles . I was doing some pulls on Saturday in my G and I noticed that it was not pulling the same. When I floor the throttle , the rpms would drop and then go back up and continue pulling . This has never happened before , I would go all the way to 5k rpm and then it would drop about 500 and then go back up till redline. This most happens in 3rd gear and up . 1st and 2nd seem to pull find , no issue . I’m guessing the car is in limp home mode ,I’m not too sure . There is no CEL and I scanned the car and it throws off no codes . When I’m driving normally and slowly the car seems perfect. Even at idle it sounds flawless . It’s just when I’m getting on it and mashing my foot on the throttle will the rpms drop and then go back up , it’s take forever to reach high speeds and is noticeably very weak to me. Has anyone else had this issue, or who would know what going on ?

 

Is your slip light coming on?

 

no it’s dosent come on.

 

Start with the easy/basic things first - clean/replace air filter? spark plugs good? are you using good premium gas (91+)? Maybe try checking/cleaning the MAF sensor.
The PO of my G neglected to change the spark plugs regularly, and at ~158k (two weeks after I bought the car) my G was coughing hard above 4k rpm and I had a check engine light. The plugs had about .090" of gap . Fresh NQK LFR5AIX-11 plugs solved that problem.

 

An rpm drop when you floor it is a classic indication of a vacuum leak. Check EVERYTHING, intake tract, entire PCV (all 3 hoses) and the brake booster line. Something is leaking air between the MAF and the throttle body, or the PCV, or the brake booster hose. If you can turn the hose by hand easily it's leaking.