so a few weeks ago , i'm out and about just doing every day stuff in town. i come out of the store , and notice that my " check engine light " is now on. a few days later i took my car in to see what was going on. the auto place did a computer scan or whatever they do.. and they pulled a " p 0171" lean code . they told me they didn't know exactly what it was unless they did further inspections ,, i don't have the $$ to throw at it , so i just kept driving with my check engine light on.. well about a week has passed ,, and all of a sudden,, i start my car,, and the check engine light is now off. ,, any opinions or thoughts on what this could be or what would cause the CEL to come on , ,then off would be helpful. ,, i have '99 gs300 with 195k ,

 

you may have a slight vacuum leak or you probably just need to clean your mass air flow sensor.

 

Clean MAF sensor, check for vacuum leaks, weak fuel pressure, last would be bad a/f sensor

 

^ ^ Like the others have said, start with the cheapest first, being cleaning your MAF sensor, if that doesn't help then check for vacuum leaks, PCV valve, then fuel filter and/or pump. If you have no other drivability symptoms I would think it shouldn't be anything major.

I lived with that CEL code for months; I have a thread here that you would have come across if you used the 'search' feature, with suggestions and things I tried. Mine would also bog down under heavy acceleration, had really low RPMs at idle especially when hot, and would occasionally 'die' when coming to a stop or approaching a turn/corner.

It turned out my fuel pump was weak; replaced it and now everything is working like it should.

 

thanks for all the input everyone. my car has been getting good MPG about 360ish per tank, city/hwy ,, although it does have a low idle about 400 -600rpm's once it warms up. also when i start my GS cold in the morning i have to give it a bit of gas for about 10seconds or else it will die , and this is only when its been sitting for more than 6hours or so and its cold. sorry i didn't mention that in my OP. any new thoughts ?

 

Clean tb if car fails to idle. Computer will calculate wrong load if throttle plate has gunk buildup

 

, i called a local repair place , and they told me they can clean the throttle body for 35$ . i told them i would check back to make an appointment, is that a good price ? i'm not very good at working on cars , so i perfer to take it in.

 

u can clean it for $5 DIY lol

 

i'm not very good at working on cars . is it easy to do ? is there a link to a DIY ,, i could only find the gs400 DIY , is it the same on a GS300?