CEL P0171 help
 

Hi all, anyhow some background info; 2006 shinka rx8, just had coils plugs and wires replaced less than 7k miles ago, it has an RB cai, GTspec header, and hks hi power exhaust. I don't premix and oil is change regularly between 3-4k miles (usually 3k but I admit sometimes i get too busy and it'll go an extra 1k miles before changing). Anyhow, recently at start up the car has started to randomly throw a CEL and using my reader i pulled a P0171. Now the CEL only comes on at start up, and will usually clear itself at start up a few days later, the CEL came on for the first time a month and a half ago, then randomly turned off 4 days later when i started the car after work. I do mixed driving, some spirited and some moderate keeping it below 5k rpm, but there are no symptoms of the car losing power or being sluggish, and the CEL never comes on while I'm driving.

Today however, after eating lunch I started the car and bam CEL is on. I read the code and again it is a P0171. I went to autozone to pick up some oil and started the car and the CEL was off, then after a few minutes the CEL came back on. Again, the car feels perfectly normal, idle is smooth, no power loss or dips anywhere throughout the powerband, or atleast I don't feel anything when i give it full throttle; and so I am stumped. Took the MAF off and it looked pretty clean although i have yet to clean it with electronic parts cleaner, and again the light just came on for the first time 1 1/2 months ago after i started using chevron instead of shell (don't know if this has any correlation to it, but maybe?)

Anyhow, any help or suggestions would be much appreciated, the local rotary shop I usually take my car to is closed until monday and even then my schedule is always pretty tight. Thanks in advance and sorry for the drawn out story.

-Jeff

update: went to autozone and bought some crc mafs cleaner, upon inspection the bulb had a pretty dark black coating on it, and the sensors themselves were probably pretty dirty as well, cleaned it and reset the code with my reader, no cel yet upon start up of the car, so we'll see, any other suggestions would be much appreciated. Thanks

-Jeff

The "bulb" (or the IAT) is normally a dark brownish color.
Did black residue come off that when you cleaned it?
And did you actually see the MAF wires to know if they were dirty or are you just assuming they were?
Did you spray/soak the MAF wires with the cleaner too or just the IAT?
Hopefully doing what you did fixed the issue. Guess we'll have to wait and see.

And that code is a "system too lean" error, so it doesn't have to be the MAF.
Could also be a leak in the intake, bad front O2 sensor, coil failure, compression failure, etc.

1). Yes, black residue did come off the IAT when i cleaned it.
2). Yes, i did inspect the MAF wires and they were dirty.
3). I soaked both the IAT and wires with the cleaner.

I checked all the connections for my rb intake as well as all the hoses, and everything was ok. Coils were just replaced so I'm hoping they aren't failing already, had a compression test done at 39k miles, I'm now at 45k and at the time the compression test was done, I was told it was perfect. As for the O2 sensor, I have not checked that yet, and since I don't have my own garage anymore (underground parking garage) I can't fully work on my own car =[. I'm hoping that it was just the dirty mafs that was throwing the cel, thanks for the response and now i guess i play the waiting game.

same code! and ive been using chevron all the time lately

i saw in another thread that it may be the fuel pump i guess now ill check the MAF and my aem cai, first and reset the code with my reader and see if it reoccurs. before i check anything else and hold off on ordering that walbro fuel pump from BHR

and that MAF was nasty....... one side looked new and the other side looked like it had been spray painted black!..... i cant believe i left that out of my cleaning routine but i reset the codes and went on a 20 minute drive and well now theres no code so far ill see if it comes back