One of my friends has an 09 Ralliart. Mods include AMS intake and GST boost pill. Getting a P0171 cel and have noticed rough idle, revs drop, when the cooling fans turn OFF. This is not the hot air into the intake / under hood turbulance problem as we have added an extended baffle to the AMS forward facing one and then even fabed a three sided aluminum box AND it occurs with the hood up as well. Car ran fine for 20K miles on an AMS tune before this problem showed up. Have cleaned MAF and tested with MAF from another 09 Ralliart. Have tried GST v 2.5 tunes and OEM tune with OEM pill. There are no pre O2 exhaust leaks and the spark plugs have been changed and gap verified. Also this isn't a low voltage issue as the problem is the same with or without a high wattage stereo amp connected and powered.

Car pulls like a beast for a Ralliart under throttle.

Please help my buddy out.


Edited to add: Checked all vac lines and no problems there either.

 

Seeing as how I'm getting so many replies....LOL

How about any info on adjusting the idle on an 09 Ralliart using Ecu Flash.

I've looked at the ROMs but unlike for the Evo X which I own and normally work on the idle tables are not available. Is this accurate or do I need a different xml file?

 

I realize this is a bit old, but it sounds more like a MAF scaling issue than anything else...

When I first put the CBRD velocity stack on mine and hadn't fine-tuned the scaling, I could literally blow on the filter element and get the car to stumble.

 

Did you solve this one? I'm having something similar.