Vogel1118

So since my 98 gs400 has been giving me some acceleration problems. And now that my check engine light is on...three codes showed up.. P0441,P0446,P0505...any suggestions on where i should begin the repair process???

badblackgs

iTrader: (1)

po505 is erratic idle speed usually due to loose air intake hose. the code sets when there is an air leak after the throttle body and the engine computer is doing everything it can to maintain a steady idle. and since you have two evap codes i suspect possibly the evap lines on the driver side of the motor above the valve cover are torn or came loose from a bad driv. side engine mount. purely speculation since i dont have the car in front of me to diagnose but check in that vicinity first.

captainva

iTrader: (1)

I think that I have this same issue but its not throwing any codes yet. The idle is very inconsistent and it recently almost died when I turned on the AC at idle. Whats the best way to troubleshoot and find a vacuum leak like that for someone working in their driveway. I've heard of spraying starter fluid but that seems pretty sketchy

jeffy

nah it isnt really that sketchy at all. use the little tube that comes with the can to help pinpoint possible problem areas, and to make sure you can isolate where it is spraying to so you dont get a reaction and not know exactly where it came from by spraying too large of an area at once.

badblackgs

iTrader: (1)

agreed. but having a scan tool to show fuel trims helps isolate it.