99 two codes

My sons 99 3.0 liter has no codes til yesterday. He changed air filter then seems like right after that the codes po171, and po174 were there. My code reader says system to lean bank 1 then other says same but bank 2. Was wondering if mass air flow since changed filter but was careful didnt drop etc.It seems to run almost perfect but with gas prices i want perfect.. thanks DAVE

Ofter those lean codes can indicate HO2 sensor malfunctions, but since you threw both codes at the same time, and right after air filter replacment, Id look for a loose vacuum line that might have gotten jarred while you were working on it.

if 02's check out check for proper vacvuum to egr.i had a couple taurus's with bad DPFE sensor.good luck

I got a 96 ranger 2.3l code po443 has came up anyone got any help or ideas? thanks

HELLO FLY,you need to start your own thread did search hope it helps http://www.asashop.org/autoinc/march2002/techtips.cfm

Hey fogg thanks. I actually got some cleaner at radio shack for tuners that leaves no residue. Sprayed wires in mass air sensor. As i did this i unplugged battery of course and cleared codes. No codes for a couple days. Now they are back. The only problem he is having is it cranks a while to start only after sitting all night, or after being in school all day. The dpfe sensor is new. Anyone ideas ill take them...THANKS DAVE

You have a problem that is common to both banks. The likelyhood of both 02 sensors going bad is remote but no impossible. As someone had suggested, check all vacuum lines including intake manifold. BTW when you disconnected the battery it caused the CEL to go out but after several starts it came back because the problem is still there. Hmmm...The hard start in morning - might check your water and air temperature sensors also.

Donsor i changed mass air seem to start and run perfect couple days. Last night it was idleing all sudden started runnin real low then died. Would not start even pressing gas tried and was firing but nothing. Hour later Started after about 6 seconds of cranking. Then this morning started again.DAVE

Have considered taking the vehicle in for a complete diagnostics? Where I'm at cost about $96.00 but it will pinpoint the problem using their sophisticated diagnostic machine. It may be a cheaper course to go as opposed to trying this and that which ends up costing you time and money. I had this done with my '91 Mitsubishi 3000GT SL when it was jerking at low speeds and the diagnostics pointed to a "lazy 02 sensor" and a "malfunctioning EGR temperatue sensor".