P0171 CEL

[mightymouse402]

Hello all,

Haven't posted/been on here in a while. Honestly don't even know if anybody will respond but let's give it the old college try. I have been having a CEL with P0171 code for the last few months. I've changed one of my O2 sensors before the catalytic and I've just recently changed the MAF sensor too. The CEL will clear for a few days at a time, but when I go on long drives that's when it comes on. I've spent more than 300 bucks trying to fix this and the same darn CEL still keeps on popping up. I changed those parts because that's what I seemed to be finding was the problem in other online forums. Any helpful responses would be greatly appreciated. Thanks!

I have a 1999 Toyota Solara that's pretty much stock with the exception of an Injen intake with the CAI extension.

[Gregtrd]

You're trouble shooting in the dark, you need a scan tool to check your fuel trims and check for leaks.

[dinoxor]

I had the same problem as well and was able to semi-diagnosed it to be my Injen intake.

If you connect the hose in the front that goes from your pcv/blow-by (I'm still not too sure what it's called) to your intake then there is a SLIGHT possibility that the oil that passes by may foul your MAFS and will make your reading all wonky.

You can use my thread as a reference: http://solaraguy.com/viewtopic.php?f=2&t=53939

I ended up with this : http://solaraguy.com/viewtopic.php?f=2&t=54007
I know it's ghetto rigged, but once I have sufficient funding, I'll implement a proper oil catch can.

After 2 years, the codes appear MUCH less frequently.
If a code does pop up, usually during WOT, it would disappear the next time I start the car.

Hope this helps and good luck.