Vehicle won't rev above 2200rpm, dealer couldn't replicate
 

2005 G35 6mt sedan, 26k mi. The vehicle is stock except the resonator is removed. Driving along yesterday, all of a sudden the engine started acting weird. I went to accelerate normally from a stop, and the car stalled. Restarted it, tried again to accelerate, and it wouldn't rev above 2200rpm, Idle bounced around then stayed at 1200rpm. I was near the dealer, so I limped it there. Drove fine, but anytime it got near 2200, power would cut out. Felt like the rev limiter kicked in, so I checked that and it was set at 6800 as usual. It wasn't backfiring, so I don't think it was spark related. The dealer looked at it, there were no codes and they couldn't get the car to duplicate the problem, suggested it was worn tires and the TCS kicking in, which doesn't explain the high idle. I don't think it is bad gas, because I put 91 in it from a Shell that I have never had problems with. Anyone had a similar experience, or have an idea of what could be going on?

limp mode...is there a CEL? did you try resetting your ECU?

No CEL, they couldn't find any codes, and I'm not sure if they reset the ECU, though I didn't try that. Shouldn't the OBD catch if the vehicle went into limp mode even if there is no code?

the only times i have heard of a VQ stumbling and not being able to rev over 2k-2.2k rpms, it was a bad maf. i would think as you have stated that the CEL would trigger but are you sure they ran codes? there have been instances of ghost codes that pertain to items like the knock sensor where the code is present but the light is not triggered. have you or anyone else replaced the air filter lately where the wires going to the maf could have been damaged?

if it wont go over 2200 why can't they replicate it?

1+ on MAF sensor. Try cleaning it. Unusual problem, but it doesn't sound like its a serious internal problem. More of a sensor than mechanical problem.

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Was it raining by any chance? Water leaking in to the harness can make the engine do all kinds of weird stuff.

They couldn't replicate it because I brought it in at 4pm and they didn't look at it until the next morning. Haven't changed AF recently, hasn't rained here in a few days, and I didn't go through any puddles. It hasn't acted up since, but I'll clean the MAF if it does it again.

I had the same problem when I accidently oiled a non oiled filter and put it on my car. The filter couldnt breathe at all I guess, I drove half a block and she wouldnt rev over 3000k. Check your intake tube, somethin could be loose