Do you have alldata wmburns?
I have built up a library of Ford service manuals and wiring diagrams covering 1992 through 2011. It takes up many Giga bytes on my computers. I use these manuals all the time and find the information critical to the repair process.
xpyder, taking a voltage measure is NOT going to fix the problem. It's meant to give information where to focus trouble shooting.
The request was to measure VOLTAGE between two wires with the key on. The TPS wire colors given are BR/W and GY/R.
BR/W is a brown wire with a white tracer.
GY/R is a gray wire with a red tracer.
This is ONE measurement with one test lead on one TPS wire and the other test lead on the other. The reading should be about 5 volts. If not, this indicates a problem.
The TPS and other engine sensors are on a 5 volt VREF circuit with a separate ground (the GY/R wire). Taking measures to chassis ground serves little purpose.
My gut tells me that this problem is either:
- A base motor problem. IE, very low compression. That's why I wanted to know the engine vacuum.
- Vacuum leak.
- Low fuel pressure.
- blocked exhaust
- A sensor problem such as bad MAF or the PCM has switched to "limp in" mode.
If in limp-in mode, the PCM will not allow the timing to advance. This will limit the RPM's. To me this sounds similar to the OP's reported symtom.
For another test to get information, what happens if the MAF sensor is disconnected at the electrical connector? Does it run better? Note, this will throw a new DTC but it's OK (for testing).
Multiple requests have been made to have the DTC codes posted. The exact codes may offer the clue needed to unlock this problem.
An ODB2 scanner that is able to monitor opperational data may make very short work of this.
Remember there is no elevator to success. You have to take the steps.