96 Ford Thunderbird Check Engine Light

start with a fuel filter, they are lots cheaper than all those sensors and should be replaced every 25K or so anyway. A plugged one will give you a lean code. If that doesnt fix it, it's time to get a fuel pressure gauge.(also cheaper than all those sensors)

I should have added that its a V8, I will change the filter tonight what pressure should fuel system be at? Is this with key on engine running or just key on?

Lean can also be caused by a vacuum leak. I just fixed the same codes on my '95 V8 by replacing a short rubber hose. The PCV valve has a short rubber hose at the valve, a metal line, then another rubber one to the throttle body. Mine had a bend at the TB end and a huge hole by the time I found it. I couldn't see it but I heard the vacuum hiss with the engine running.

PoD

Fuel pressure should be checked when fuel demand is high.... a brief wide open throttle on the highway should tell any tales. While a pump can easily create pressures in spec when fuel demands are low, this same pump may be tired and unable to supply sufficient volume at high demand conditions.... this insufficient volume will show as a drop in pressure.

"" wrote: > I have a check engine light and the codes that are pulled are > 171 and 174 > bank one and bank two too lean, I have changed the O2 sensors, > the mass > air, flow sensor throttle position sensor and the light comes > back on, > short of buying a break out box for 500.00 I could use anyones > advice

well you wasted your money on buying o2 senors and maf sensor, MAF sensors can be cleaned I never herd of a TP sensor creating this code you have a vacuum leak either intake manifold gaskets or vacuum lines check them very carefully If you have a scan tool curious what is your Long fuel trims and your short fuel trims long should be 0% +- no more than 10% short should be hovering around 0% this is why it pays to bring your vehicle to a dealer, I would have fixed your problem for less than you spent on wasted parts

If your fuel filter is restricted you will notice a lack of power at wide open throttle ck the vacuum lines for leaks see it all the time

Its nice if you can hook up the gauge and run the hose from under the hood and drive the car. That way you can see the pressure under real conditions. Just take a fire extinguisher with you :)

I do know that the only time the light comes back on is when she is getting on the interstate, around town it stays of only when

Sorry Marty but unless you live around the Space Coast of FL it would not be possible and since the car had been to a few services centers and they all said O2 and MAF even the local ford dealer, I do thank you for you in outs and will work on the fuel pressure and the vacuum