A few months ago I was driving and the engine light came on (occasionally the light came on for an evap code that wasn’t a huge deal so I wasn’t too worried about fixing it immediately) and as I was driving the car started puttering like it wanted to stall. So I pulled over and turned the car on and off and it was still having that issue and it couldn’t keep the rpms high like the power was just cutting out. So after I read the code I went and got mass air flow cleaner and cleaned both maf’s. After that the car still had the code but it wouldn’t putter or stall like it wanted to before. So I continued driving it. The car would hard shift every gear and would shift deep in the red line if I kept it in automatic. When I took turns hard and lost the slightest bit of traction, the car would cut power and the rpms would just drop under 1k. It would also cut power going over any sort of bump, rpms would just go below 1k and I’d have to wait a few seconds for the car to get power again. I drive this car hard and it has 175k (had 159k when I got it last year and it seems to have been taken care of nicely) on it but I’ve never had an issue and always has ran like new. My friend is a mechanic and we tried new maf’s but that turned out to not be the issue, we tested all the fuel injectors and they all were fine. I know the issue can be the fuel pump but judging from the things we’ve tested that’s a very low probability. I know it can be vacuum lines or wiring but if anyone can help me out here that would be appreciated a lot

 

P0171 means a lean condition on bank 1, thoroughly inspect the intake pipe for any cracks/leaks, that's the usual culprit.

I would also pull and inspect the plugs.

 

Alright I’ll definitely give it a look, thanks man. I believe my guy went through and checked that but I’ll mention it again

 

Have him smoke test the intake tract, quick and easy way to find leaks. Plus smoke machines are cheap.

 

that’s a good idea, I hope that’ll find the issue

 

So my guy did a relearn today and now the code C1130 is coming up which is an ABS engine 1 fuel cut system fault. Does anyone know if this could be causing the P0171

 

Not sure about the V36 platform G35 but on mine the C1130 is the front right side airbag (USDM passenger side, side impact airbag).

I suspect it's the same code on yours. Unrelated to P0171

 

so I got the car back the other day, drove it over 200 miles in the last 2 days and it seems like the relearn fixed the P0171, he did replace one MAF with an hitachi also. The car idles between 600-800 again, no hard shifting or shifting in deep redline, all very smooth shifts, and when traction is lost or the slip light comes on it doesn’t cut power. So I’m hoping I’m in the clear because this car is so fun to drive. The only light that keeps coming on is the p0455, but that’s just an evap thing but it’s been on for a year and I think I know the issue but if anyone has any insight on that definitely let me know.

 

I had the code also. I changed the 02 sensor and it kept coming back. Come to find out I had to clean the MAF sensor and I had a small leak on one of my intake hoses. Hasn't come on since...