Codes are reading low tps voltage, mapps high voltage ignition on low voltage at idle. Idle surges sputers and stalls when driving. Replaceed mapp and tps with no improvment?

OBD code 121 is usually a TPS.
Take a look at this site.
P0121 Throttle Position Sensor Switch Circuit Range Performance Problemvar...

Have u checked the cadeletic converter. It can do funny things

typically this vehicle utilizes a map sensor or what is known as a speed density system the vac operated devices that draw enough to cause it to stall are the 1. brake booster 2. pcv system 3.any of the rest of them would cause a fluctuating idle but the pcm could compensate we know the idle air control system is working because the idle surges so i would first remove the fresh air hose from the throttlebody the dry dirt around the butterfly valve accumulates chocking the airflow off and causes a low idle this is known as coking and is very common also check for EGR codes if egr solenoids 1 or 1,2 or 2 or 3 are stuck open this will cause a low unstable idle or stall and the tps voltage at idle should be checked 3 wires 1 wire should be ground 0.v 2nd wire should have a 5v reference and third wire is what is known as signal return it should read at idle around .5v to 1.v if it is not in this range then it will cause the same symptoms

This is where proper diagnosis comes in...as the TPS sensor voltage low because of a failed TPS sensor? Or was the TPS voltage low due to low battery voltage at the control module? Did you bother to check for the proper voltage at the TPS sensor connector before throwing parts at the problem? If the battery voltage goes low, it is NORMAL for the engine to not idle correctly. Low voltage at the control module can cause the computer to lose all of its "learned" data. It will have to "re-learn" how to idle the engine. This can sometimes take a few days. This is exactly WHY I keep telling people to not be disconnecting batteries in an attempt to "clear" computer fault codes.
If your battery has been going dead, you need to properly test and diagnose your battery and charging system. If this system is not working correctly, there is NO WAY your computer network can function correctly. - this MUST be diagnosed and repaired FIRST!

It could be a vaccuum leak, mapp sensor, maf sensor, oxygen sensor and many numerous other things. If the engine light is coming on you should be able to retreive the error codes that are stored in the computer.

Refer here to read your codes http://www.fordfuelinjection.com/?p=13 then continue down on this page and you can see what the codes mean.

if this helped please leave a good rating.

thanks and good luck

A P0123 code means that the computer has detected that the TPS (throttle position sensor) is reporting too high a voltage.

Symptoms may include:

• Rough idle
• High idle
• Surging
• other symptoms may also be present

A code P0123 may mean that one or more of the following has happened:

• TPS not mounted securely
• TPS circuit short to ground or another wire
• Faulty TPS
• Damaged computer (PCM)

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, carefully inspect all wiring and connectors that lead to the TPS. More than likely the problem is with the TPS wiring. Check the voltage at the TPS (refer to a service manual for your vehicle for this specific information). If the voltage spikes or is too high (over 4.65 volts with key on, engine off), then that is indicative of a problem. Carefully trace each wire from the TPS wiring harness to check for breaks, rubbing against other components, etc.

vacuum leak or egr valve stuck open

Wow you have replaced a lot of stuff. Lets go back to the Fuel pump. When you replaced it did you replace the hose between the pump and the sending unit. These are common for splitting. Have you hooked up a fuel pressure gauge to check what pressure you have? It should be real close to 13 psi and should raise to at least 18 or 19 when you pinch off the return line.

those sensors could cause the issue, clean the MAF 1st, also clean the idle system using the following procedure, the IAC can cause cruise surge. I use this to cure these problems all the time.

Here is the most common cause of surges and stalls and low idle, it is the idle speed control air-bypass valve (IAC) and throttle valve, they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

yes checked fuel pressure and replaced the fuel filter, checked the mapp sensor,tested throttle position sensor, has strong spark, 50psi fuel pressure, fresh tune up, runs real rich and rough idle but wont rev up like fuel injectors arent speeding up, also checked exhaust. thanks julius