If you realize you put your throttle position sensor on wrong on your 2000 expedition will that damage the part ..Can you always go back later and adjust

Yes

Hi Steve,what exactly is it doing?

it could be the o2 sensor or the throttle position sensor .

code po122 is for your throttle position sensor. po155 is for your down stream o2 senor .po135 is for your bank 1 sensor 1 o2 sensor. po102 is for your maf sensor

The TPS is located on the side of the throttle body closest to the front of the vehicle. There are two electrical units attached to the throttle body the other being the IAC or idle air control. The IAC is usually a cylindrical object about 3" long and 1 1/4" in diameter.

might have a bad temperature sensor or thermostat . and if the rpms are going crazy there is a tps sensor throttle position sensor and an idle air control valve also check the wires going to these devises i had a wire cut and replaced the tps and it still din`t fix it it was a bad wire do a little looking around see if wires are touching or rubbing on things they are strapped to . also do you have a check engine light on . and have you done a tune up lately

I'd bring it back to the shop that put in the throttle body and have them check to see if the replacement was defective or failed. If not, you may have a bad throttle position sensor [part of the gas pedal] I'm assuming it worked fine for a while after the repairs with no problems then suddenly started acting up again. I've replaced a bunch of throttle bodies but only one position sensor so far. There's always the chance that there's a bad wire somplace or some other more exotic problem but I'll bet you'll find it at either the sensor or throttle body. Good luck, hope this helps!

Sounds like a Throttle Position Sensor. Don't let a Dealer tell you that the whole throttle body needs to go. I just looked up a Motorcraft TPS sensor yesterday for a 2006 Expedition. Amazon,free shipping $59.91. Auto parts store $65 to $75. Two T-20 Torx screws and a 10 min job.If that is your issue. Should at least put a scanner on it, to check the code that set that light. Expect more of those type of check lights as it gets older.

The mass air flow sensor is in the air intake between the filter and throttle body. The filter is in one half of the air box and the sensor is in the other. You should have a wire harness running out the bottom and a connector toward the top. When you split the chamber to access the air filter, tip up the half to your left and you will see it. Sometimes you can get by with cleaning it, but you may not have a permanent fix. You must ONLY use a cleaner that does not leave ANY residue, such as brake cleaner. Make sure the connector is fully engaged, and check for bent or pushed back pins. Sometimes the pin locks in the hardshell were never fully engaged and the pin connectors push out the back of the plastic hardshell connector. Hope you save some cash on this one. I realize how costly repairs are these days. Well wishes.

it means that the throttle position sensor is going bad, have it replaced.