System running lean/rough idle 1999 3.4 v6

I checked all my vacuum lines -everything is secure..
I cleaned my throttle body...
it could be mass air flow sensor but it didnt look dirty- what does it look like if its dirty?(i didnt clean it)
Idle air control valve may need cleaning/ replacing?
i used to have a cold air intake but took it off months ago and problems and check engine light(system too lean) just arrived?
what should i do to fix this issue? I like to do all the work on my truck to avoid paying for labor and diagnosing....
Anyone else have this issue or any advice on what it could be???
thanks in advance

 

bump

 

yeah forget the # but it read engine running too lean

 

0171

 

All vehicles these days are so buried in electronics & emissions that its almost impossible to just "have a hunch" & be right cause several key emissions equip. can fail & cause the same condition so narrowing the code is pretty key in gettin' to the heart of the matter so ya don't waste alot of time and $$$$ just throwing at the problem, anyway need more info, miles ?, could be an 02 sensor, a plugging up fuel filter,(check fuel pump pressure) a CATALYTIC getting ready to shit. As far as vacuumm lines go you can't just give them the ol' once over & assume its all good, with engine running, take a little aerosol chemtool or just about any other type spray, & while idling spray the lines & connections, & other hard to get to places & see if idle changes noticeably, if idle speed picks up then you can start looking for a VAC. leak somewhere, but still you really need to isolate the codes & defs. so you can have a better chance of fixing your problem in a timely manner.....GOOD LUCK ....

 

i have 145,xxx miles do you think the fuel filter could go bad?
Also, what does a dirty MAF look like? sounds dumb but mine didnt have any dirty gunky build up on it?? could it still be dirty?
thanks

 

thanks chris and 4wd -new fuel filter is only 20 bucks so might as well change it...
I will spray down my MAF as well..
ITs weird because the rough idle prob came up about 2 months ago(while at a stop light, idle stumbled) but then went away but now its back.. its still drives great under load though...
frustrating as hell

 

i had the same problem for months man, drove me crazy. the cel would come on and it wouldn't just be system to lean, it would be 3 or 4 codes. i cleaned the maf thinking that would help, didnt work. replaced maf, that didnt work. cleaned both o2 sensors still no luck. so i decided to spend the couple hundred bucks and buy a new o2 sensor(bank 1 sensor 1, the one closest to the engine). Worked perfectly, cleared everything up. Pain in the ass to change though.

 

4 years ago toyota wires and bosch platninum 4 plugs top dollar shit never caused anything but good

 

that maybe so... however the truck has not had an issue with plugs or wires.. its been four years of perfection! that cant be the issue
any other suggestions?

 

If thats the case why would have ran fine for 4 years without a single prob?