TPS problem?

[Ricco4592]

My explorer sport with the 4.0 SOHC has a wierd idle. it'l rev up as usual, then die down to about 500, and go to regular idle. now during this process there a loud knocking noise. I disconnected the TPS and it went away, but then the truck threw the PO122 code so i plugged it back in, same symptoms and noise came back. I want to try and replace it, but the screws holding it on wont budge and I really dont want to strip them. Is there any easy way to get them off? the noise also goes away after i drive it for about 5 minutes, it just makes this noise everytime i start it.

 

[2000StreetRod]

TPS Test Procedure

I suggest that you test your TPS before replacing it.
TPS Test Procedure
I doubt that it is the cause of the knocking noise you hear at engine start. If the noise sounds like marbles rattling around in the engine then you may have worn/broken timing chain guides or tensioner. Try using a length of hose to isolate to the source of the noise. Lower right rear could be cat shields. Upper right rear could be timing chain guide assembly. Upper left front could be timing chain guide assembly. Lower center front could be primary tensioner. If the noise is in the front you can disconnect the serpentine belt and run the engine for a minute. No noise means its one of the accessories: belt tensioner, belt idler, alternator, power steering pump, or A/C compressor. Also make sure the harmonic balancer inner and outer sections have not separated.