hey, i just bought a f250 XL (it has the 150 cab) 99' got it for a steal cuz it had a couple issues, but ive got most worked out, still havein a couple problems.
the big one is the idle, when i first turn the car on, it does one of two things
most of the time it rev's up really high, theres no rpm gauge, i still need to go get one, so i dont know how high its goin, but it gets up there.. id say around 2000-2500
the other thing it does sometimes, if it doesn't spool up, it will go so low, i cant believe it doesn't stall, it'll do that for a little bit, then spool up real high.. of course when i put it in drive, it calms down to what it should be
i suspect maybe the iac, im still tryin to get around to cleaning that,
by the way, when i got this truck, it used to be a work truck.. it was extremly dirty, looks like he never cleaned the air filter, till he sold it (there was a brand new one in it) but i took the air intake off, i could literaly write my name in the dust in the carb.. no good

when i plugged the computer in it(check engine light is on) it told me bank 2 is lean.. code: P0174 ..but i dont know codes

theres 2 other smaller problems, that im not to worried about yet
1: the cooling fan engages constantly and never turns off.. not all the way though, sometimes it does engage all the way, and it sounds like a tornado

2:the exhaust makes a ticking noise.. im not sure if these trucks have a exhaust valve that could have gone bad or what.. or maybe it could be an egr issue? which could also explain why the engine doesn't run great, but wouldn't that make it rich if the egr was acting up?

any advice helps, thanks

 

by the way, ive cleaned the maf sensor, and the second one in there, whatever that one was, and ive checked just about every vaccum line, theres one line that goes to the back of the block up against the fire wall that i couldn't get to.. but on testing it, i was getting between 14-17.. lbs of mercury? (im not really sure how to write that) which according to the manuel, is low, but acceptable, its says you should be getting around 20 average.. which i do get, when the engine is at a higher rpm

 

The P0174 is an OBDII basic code that means "bank 2 is lean." We know that. What it really means is 'hey, I'm at the clip of either 25 or more percent rich and i can't see the O2 switch.' There is good chance the idle and this are totally related (though since I can't see it, I'd probably be wrong). Check the vacuum lines/tubes all over the engine. Pay very, very particular attention to the PCV line where it comes off the right V/C. Trace it with your fingers and take the valve out of the cover. Look very closely for the rubber Tees and connectors. See if they've deteriorated and are leaking. This is ultra-common. I know it's a pain reaching for the one on the back of the manifold, but it must be checked. If all is good, 14-17" Hg of vacuum seems low at sea level (here in denver, that's good!). If you have a scanner (just about anything that will read OBDII generic pids will even work), check the o2's yourself. If you just can't find any leak, spray carb cleaner or brake cleaner over the top of the engine and which the affected o2 for sudden life signs; if it comes back, then there's your leak. Watch out for the IAC, as cleaner sprayed around it can get sucked in. Also, check the MAF and clean it if necessary.