1994 Ford Thunderbird check engine light on auto with air

code p 0141 refers to the heated oxygen sensor (HO2S) 2 bank 1 in the exhaust manifold
check wiring and replace the HO2S unit
code p0171 refers to system too lea bank 1
among the causes is the HO2S which controls the air fuel mixture settings for the ECM so replacing the HO2S for the first will probably fix this code
code p0174 refers to system too lean bank 2====causes for this code include the following
intake / exhaust leak---fuel pressure/pump---injector/s---AIR system---hose connections

You should be replacing all upstream oxygen sensors,
the ones at the inlet or pipe before the converter,on all
your vehicles at 100,000 miles

Go to Rock Auto.Com & buy two & install yourself

NTK 22060 $26.79 ea

p0171 is lean exhaust bank one ( passenger side) and p0174 is lean exhaust bank 2 ( drivers side). First we need to look for vacuum leaks, low fuel pressure, Intake air leaks after the mass air flow sensor, pvc system. Because you have both sides lean I would start looking at these spots.

My advise is to look at what moistcabbage had to say about your problem. Then I will add a little advise:
Put the P0171 on hold until you have a verified fix for the other 2 codes. Here's why:
.
A misfire causes raw fuel and air to be shoved down the exhaust as an unburned mixture (After all. that's what a misfire is.) This can cause the free oxygen level in the exhaust to rise and cause the lean code (P0171) From the EGR code that you have, I can tell that you have the 2.0L engine in your car. (This is not a valid code for the 2.5L) In this case, moistcabbage is sort-of correct. Thiscode actually indicates that the EGR valve does not move when the computer commands the EGR to open. (Which SHOULD also be producing a P0400 code, which is EGR no or low flow.) If P0400 is not present, then chances are that this is caused by the EGR sensor "lying" to the computer and telling it that the EGR is not opening when it really is. However, it also may be telling the truth and the computer just hasn't picked up on the low flow issue yet. Anyway, if the EGR is not moving, it could be caused by a vacuum leak, which will also cause your P0171code.
The logical order of this would be to check for obvious causes of misfire like the spark plug, wire, coil, and fuel injector and correct as necessary. Also check the EGR system out to find out what the cause of the EGR not moving code is. (And repar as necessary) Then clear the codes and drive the car to see if the P0171 code returns. If P0171 returns and the other codes stay gone, then you will have to check into oter possible causes of the lean code. Otherwise, I would not waste any time checking into a lean condition at all before the other two codes are confirmed fixed.

www.engine-light-help.com/generic-check-engine-light-codes.html

have code pulled from light when code is pulled and problem fixed light will go off could be hundreds of different things the code will tell whats wrong by haveing it pulled

p0171 and p0174 are common issues the most of the time it is a vacuum leak check all vacuum lines have seen the vacuum line on the back of the air horn bad several times.

try to disconnect battery for five min and reconnect to reset computer. berrydalewolf

there is no reset switch,either take it to a big name auto parts store and have them use a scanner to give you the codes and turn off the light,or just disconnect battery for 3min and the light should go out. the first suggestion is the better, this way you will know what turned the light on in the first place, get back to me if you need more help, please rate my fix

EGR has no flow