Help Please (Idle Problems)

[BlkExplorerSport]

I bought my 99 Sport about 4 months ago and starting about a month after i bought it i've been having an idling problem. If i start the truck it will rev either to about 2800 Rpm and then it will just drop down and completely stall. or it will start and go to about 500 rpm and just drop down and stall. only way to make it not stall is to hit the gas once after it starts to drop. i had engine codes on it which were p171 and p172 if i remember correctly. anyways they meant. (Fuel System Bank 1 - System To Lean) and (Fuel System Bank 2 - System To Lean) i have been having to hit the gas to keep it started so using my remote start doesn't help because even if the remote start works, it just dies after being started. anyone know what this is ? i really want my truck to be in good working condition because i plan on keeping it for many years. I dont want to pay ford $300 for a diagnostic test.

 

[RockyMtnHigh]

I bought my 99 Sport about 4 months ago and starting about a month after i bought it i've been having an idling problem. If i start the truck it will rev either to about 2800 Rpm and then it will just drop down and completely stall. or it will start and go to about 500 rpm and just drop down and stall. only way to make it not stall is to hit the gas once after it starts to drop. i had engine codes on it which were p171 and p172 if i remember correctly. anyways they meant. (Fuel System Bank 1 - System To Lean) and (Fuel System Bank 2 - System To Lean) i have been having to hit the gas to keep it started so using my remote start doesn't help because even if the remote start works, it just dies after being started. anyone know what this is ? i really want my truck to be in good working condition because i plan on keeping it for many years. I dont want to pay ford $300 for a diagnostic test.

Since buying the truck what routine maintenance have you performed?

When buying a vehicle of that age that I intend to keep running for many years, unless I have verifiable sevice records, I would change the oil, coolant, diff fluid, transfer case oil, fuel filter, PCV, air filter, plugs and wires to start. Service the transmission, clean or replace the MAF sensor as well as check the driveline belt and pullies.

Your problem might be solved by doing any one of the above. A true lean condition is caused by either an abundance of air or a lack of fuel. It could also just be a faulty sensor sending the wrong information to the computer and engine. A faulty IAC, EGR, vaccum leak or bad intake gaskets could also be the cause.

 

[mrboyle]

Try searching IAC cleaning.