Matthew Diehm

Today, I happily purchased a used '09 G37x sedan AT w/manual mode. Got it from a reputable corporate dealership, not a hole in the wall. I've wanted one for years.
Drove it home, apx 60 miles of highway, city traffic and back-roads. No problems at all. Car seems(ed) to be running like a champ and in great shape for the year and mileage '09 135k.
Stopped at the store to pick up dinner for the fam, turned off the car etc, apx 30 minutes.
I began driving home just fine but after a mile or two, came to a stop sign and upon accelerating from the stop, the car jerked and stuttered, power dropped way down. Pulled into gas station immediately, freaking out, parked it, gave it some gas to rev it and the engine would seem to wobble and shake the car all while not getting the revs up, loss of power.
I had to get the car home as I didn't even have the new plate on yet. So, what I ended up having to do for the last 4-5 miles home, was that I found that by shifting into manual/sport mode, matching the revs as best as I could to get up to 5th or 6th gear, then I could get up to the speed limit, very jerky and boggy until reaching a high gear and maintaining speed, while still low on power, the car ran smoothly. Came to more stop signs and red lights etc, every time I tried to accelerate in automatic D, there was just no power and the transmission didn't seem to want to shift up unless I quickly switched to manual mode and got it up to a higher gear. Even in 5th, 6th or 7th gear the power was very limited as well. Got home. Parked it. Saturday night ruined. Nobody to look at the car until Monday.
I did however speak to the fella that helped me earlier at the dealership before they closed (he's a good guy, no BS) and one thing he mentioned was that perhaps during the pre-sale detailing (done just before I drove off the lot) as they power washed/sprayed the hood, maybe a sensor or something got wet and is causing failure or limp mode or something like that.
I don't know, maybe.
I've been reading about and watching videos about dirty mass af sensors, dirty throttle bodies and re-setting the ecu. Hopefully the issue is that simple and all is well, be great if I could even do it myself. If not, thank God I got a warranty lol. Either way, I plan on leaving the car alone until I have a professional look at it, as I am no mechanic and have only a basic repair/diag skill-set.
Always something.
Anyone experience something similar?

slartibartfast

iTrader: (7)

RMB5190

iTrader: (2)

Any Advance Auto can pull your codes for you. As Slarti mentioned, I'd start there.

Follow your original plan and clean the MAFs, ECU reset and perform the pedal position relearn procedure and throttle body re-learn. There's a 3rd procedure to do but I cannot remember the name for it. Basically, turn the car on and off and you should hear the throttle bodies clicking under the hood. Motorvate has a DIY you tube channel that has a ton of great information. Look for a video name "after cleaning throttle bodies" and he will walk you through each of the procedures.

Matthew Diehm

Re-set the ecu with the pedal dance and had the codes checked. Mass AF showed. Garage had it 4 hours and apparently af and throttle bodies were really gunked up. Cleaned them and put it through 10 drive cycles and everything is as it should be. They couldn't find one other thing wrong with it. Thank God. Gotta give it a couple weeks of driving to make sure the issue is solved but it's running great now. Thanks guys.

RMB5190

iTrader: (2)

135k miles, I wouldn't be surprised if they'd never been cleaned. Good to hear the issue is resolved.